I think this may be another form of an IE bug I have seen before. Make sure you clear the "Temporary Internet Files" folder via the IE's options in the tools menu and ALSO clear the Java Webstart Cache.
(
Double click the Webstart Icon the the desktop, choose Settings from
the File->Settings->Extendend dialog. Hit "Delete folder content"
).
除了清空IE缓存,也试试情况Java Webstart的缓存。