I can't create a job that uses SCM:svn:https. It falls over attempting to serialize something.

This is hudson running on linux, windows 7 slave launched via jnlp by a user in the admin group.
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Building remotely on windows7-64
Checking out a fresh workspace because C:\hudson2\workspace\production-riatest\riatest doesn't exist
Checking out https://---------------------------------------------------------------------------------------------------
ERROR: Failed to check out https://--------------------------------------------------------------------------------------------------------
org.tmatesoft.svn.core.SVNException: svn: Unknown error
at org.tmatesoft.svn.core.internal.io.dav.http.HTTPSSLKeyManager.acknowledgeAndClearAuthentication(HTTPSSLKeyManager.java:231)
at org.tmatesoft.svn.core.internal.io.dav.http.HTTPConnection.request(HTTPConnection.java:368)
at org.tmatesoft.svn.core.internal.io.dav.http.HTTPConnection.request(HTTPConnection.java:273)
at org.tmatesoft.svn.core.internal.io.dav.http.HTTPConnection.request(HTTPConnection.java:261)
at org.tmatesoft.svn.core.internal.io.dav.DAVConnection.exchangeCapabilities(DAVConnection.java:516)
at org.tmatesoft.svn.core.internal.io.dav.DAVConnection.open(DAVConnection.java:98)
at org.tmatesoft.svn.core.internal.io.dav.DAVRepository.openConnection(DAVRepository.java:1001)
at org.tmatesoft.svn.core.internal.io.dav.DAVRepository.getLatestRevision(DAVRepository.java:178)
at org.tmatesoft.svn.core.wc.SVNBasicClient.getRevisionNumber(SVNBasicClient.java:482)
at org.tmatesoft.svn.core.wc.SVNBasicClient.getLocations(SVNBasicClient.java:851)
at org.tmatesoft.svn.core.wc.SVNBasicClient.createRepository(SVNBasicClient.java:534)
at org.tmatesoft.svn.core.wc.SVNUpdateClient.doCheckout(SVNUpdateClient.java:893)
at hudson.scm.SubversionSCM$CheckOutTask.invoke(SubversionSCM.java:742)
at hudson.scm.SubversionSCM$CheckOutTask.invoke(SubversionSCM.java:660)
at hudson.FilePath$FileCallableWrapper.call(FilePath.java:1899)
at hudson.remoting.UserRequest.perform(UserRequest.java:114)
at hudson.remoting.UserRequest.perform(UserRequest.java:48)
at hudson.remoting.Request$2.run(Request.java:270)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at hudson.remoting.Engine$1$1.run(Engine.java:58)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.reflect.UndeclaredThrowableException
at hudson.scm.$Proxy7.getCredential(Unknown Source)
at hudson.scm.SubversionSCM$DescriptorImpl$SVNAuthenticationProviderImpl.requestClientAuthentication(SubversionSCM.java:1589)
at org.tmatesoft.svn.core.internal.wc.DefaultSVNAuthenticationManager.getFirstAuthentication(DefaultSVNAuthenticationManager.java:159)
at org.tmatesoft.svn.core.internal.io.dav.http.HTTPSSLKeyManager.initialize(HTTPSSLKeyManager.java:255)
at org.tmatesoft.svn.core.internal.io.dav.http.HTTPSSLKeyManager.initializeNoException(HTTPSSLKeyManager.java:237)
at org.tmatesoft.svn.core.internal.io.dav.http.HTTPSSLKeyManager.chooseClientAlias(HTTPSSLKeyManager.java:131)
at com.sun.net.ssl.internal.ssl.AbstractWrapper.chooseClientAlias(Unknown Source)
at com.sun.net.ssl.internal.ssl.ClientHandshaker.serverHelloDone(Unknown Source)
at com.sun.net.ssl.internal.ssl.ClientHandshaker.processMessage(Unknown Source)
at com.sun.net.ssl.internal.ssl.Handshaker.processLoop(Unknown Source)
at com.sun.net.ssl.internal.ssl.Handshaker.process_record(Unknown Source)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readRecord(Unknown Source)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.performInitialHandshake(Unknown Source)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.writeRecord(Unknown Source)
at com.sun.net.ssl.internal.ssl.AppOutputStream.write(Unknown Source)
at java.io.BufferedOutputStream.flushBuffer(Unknown Source)
at java.io.BufferedOutputStream.flush(Unknown Source)
at org.tmatesoft.svn.core.internal.io.dav.http.HTTPConnection.sendData(HTTPConnection.java:226)
at org.tmatesoft.svn.core.internal.io.dav.http.HTTPRequest.dispatch(HTTPRequest.java:166)
at org.tmatesoft.svn.core.internal.io.dav.http.HTTPConnection.request(HTTPConnection.java:345)
... 23 more
Caused by: java.io.IOException: Unable to serialize hudson.scm.SubversionSCM$DescriptorImpl$SslClientCertificateCredential@59b3f94b
at hudson.remoting.UserRequest.serialize(UserRequest.java:162)
at hudson.remoting.UserRequest.perform(UserRequest.java:122)
at hudson.remoting.UserRequest.perform(UserRequest.java:48)
at hudson.remoting.Request$2.run(Request.java:270)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:885)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.io.NotSerializableException: hudson.util.Secret
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1156)
at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1509)
at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1474)
at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1392)
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1150)
at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:326)
at hudson.remoting.UserRequest._serialize(UserRequest.java:151)
at hudson.remoting.UserRequest.serialize(UserRequest.java:160)