We were getting a "Can't copy file from workspace to build folder:" error when trying to view the source from findbugs. Searching online suggested that we change **/findbugs.xml to **/findbugsXml.xml, and that seems to have fixed the issue.

However, if you leave the configuration box empty, the plugin still defaults to */findbugs.xml. Also, the help files suggest "*/findbugs.xml" is correct. Should this be changed?

src\main\java\hudson\plugins\findbugs\FindBugsPublisher.java
private static final String DEFAULT_PATTERN = "**/findbugs.xml";

src\main\resources\hudson\plugins\findbugs\FindBugsPublisher\config*.properties (all languages)
src\main\webapp\help*.html (all languages)