When I try to schedule this (under Job -> Build Triggers -> Build Periodically):
"H 0 17 * * *"

I get this exception:
javax.servlet.ServletException: java.lang.RuntimeException: Failed to instantiate class hudson.triggers.TimerTrigger from

{"spec":"H 0 17 * * *"}

at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:735)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:799)
at org.kohsuke.stapler.MetaClass$6.doDispatch(MetaClass.java:239)
at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:53)
at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:685)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:799)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:587)
at org.kohsuke.stapler.Stapler.service(Stapler.java:218)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:45)
at winstone.ServletConfiguration.execute(ServletConfiguration.java:248)
at winstone.RequestDispatcher.forward(RequestDispatcher.java:333)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:376)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:96)
at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:88)
at winstone.FilterConfiguration.execute(FilterConfiguration.java:194)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:366)
at hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:48)
at winstone.FilterConfiguration.execute(FilterConfiguration.java:194)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:366)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:84)
at hudson.security.UnwrapSecurityExceptionFilter.doFilter(UnwrapSecurityExceptionFilter.java:51)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at jenkins.security.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:117)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.providers.anonymous.AnonymousProcessingFilter.doFilter(AnonymousProcessingFilter.java:125)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.ui.rememberme.RememberMeProcessingFilter.doFilter(RememberMeProcessingFilter.java:142)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.ui.AbstractProcessingFilter.doFilter(AbstractProcessingFilter.java:271)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.ui.basicauth.BasicProcessingFilter.doFilter(BasicProcessingFilter.java:174)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at jenkins.security.ApiTokenFilter.doFilter(ApiTokenFilter.java:64)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.context.HttpSessionContextIntegrationFilter.doFilter(HttpSessionContextIntegrationFilter.java:249)
at hudson.security.HttpSessionContextIntegrationFilter2.doFilter(HttpSessionContextIntegrationFilter2.java:67)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:76)
at hudson.security.HudsonFilter.doFilter(HudsonFilter.java:164)
at winstone.FilterConfiguration.execute(FilterConfiguration.java:194)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:366)
at org.kohsuke.stapler.compression.CompressionFilter.doFilter(CompressionFilter.java:46)
at winstone.FilterConfiguration.execute(FilterConfiguration.java:194)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:366)
at hudson.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:81)
at winstone.FilterConfiguration.execute(FilterConfiguration.java:194)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:366)
at winstone.RequestDispatcher.forward(RequestDispatcher.java:331)
at winstone.RequestHandlerThread.processRequest(RequestHandlerThread.java:227)
at winstone.RequestHandlerThread.run(RequestHandlerThread.java:150)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at winstone.BoundedExecutorService$1.run(BoundedExecutorService.java:77)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.RuntimeException: Failed to instantiate class hudson.triggers.TimerTrigger from

{"spec":"H 0 17 * * *"}

at hudson.model.Descriptor.newInstance(Descriptor.java:576)
at hudson.model.AbstractProject.buildDescribable(AbstractProject.java:2034)
at hudson.model.AbstractProject.submit(AbstractProject.java:2006)
at hudson.maven.MavenModuleSet.submit(MavenModuleSet.java:1137)
at hudson.model.Job.doConfigSubmit(Job.java:1136)
at hudson.model.AbstractProject.doConfigSubmit(AbstractProject.java:787)
at sun.reflect.GeneratedMethodAccessor14086.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:297)
at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:160)
at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:95)
at org.kohsuke.stapler.MetaClass$1.doDispatch(MetaClass.java:111)
at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:53)
at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:685)
... 56 more
Caused by: java.lang.IllegalArgumentException: Failed to instantiate class hudson.triggers.TimerTrigger from

{"spec":"H 0 17 * * *"}

at org.kohsuke.stapler.RequestImpl$TypePair.convertJSON(RequestImpl.java:597)
at org.kohsuke.stapler.RequestImpl.bindJSON(RequestImpl.java:392)
at org.kohsuke.stapler.RequestImpl.bindJSON(RequestImpl.java:388)
at hudson.model.Descriptor.newInstance(Descriptor.java:567)
... 70 more
Caused by: java.lang.IllegalArgumentException: antlr.ANTLRException: Invalid input: "H 0 17 * * *": line 1:11: expecting EOF, found ' '
at org.kohsuke.stapler.RequestImpl.invokeConstructor(RequestImpl.java:454)
at org.kohsuke.stapler.RequestImpl.access$200(RequestImpl.java:77)
at org.kohsuke.stapler.RequestImpl$TypePair.convertJSON(RequestImpl.java:595)
... 73 more
Caused by: antlr.ANTLRException: Invalid input: "H 0 17 * * *": line 1:11: expecting EOF, found ' '
at hudson.scheduler.CronTabList.create(CronTabList.java:87)
at hudson.scheduler.CronTabList.create(CronTabList.java:73)
at hudson.triggers.Trigger.<init>(Trigger.java:161)
at hudson.triggers.TimerTrigger.<init>(TimerTrigger.java:48)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:525)
at org.kohsuke.stapler.RequestImpl.invokeConstructor(RequestImpl.java:439)
... 75 more
Caused by: line 1:11: expecting EOF, found ' '
at antlr.Parser.match(Parser.java:211)
at hudson.scheduler.CrontabParser.startRule(CrontabParser.java:67)
at hudson.scheduler.CronTab.set(CronTab.java:93)
at hudson.scheduler.CronTab.<init>(CronTab.java:83)
at hudson.scheduler.CronTabList.create(CronTabList.java:85)
... 83 more