Somewhere in the hotspot build there are files being created with very very long pathnames.
These long paths cannot be deleted easily on Windows, anything longer that 255 can be a problem, java apps can create and delete them, but standard utilities (especially on Windows 2000) cannot delete these files.

rm: cannot remove `C:/temp/jprt/P1/B/062752.mbykov/source/build/windows-amd64-fastdebug/hotspot/outputdir/windows_amd64_compiler2/generated/saclasses/sun/jvm/hotspot/debugger/win32/coff/COFFFileParser$COFFFileImpl$COFFHeaderImpl$DebugVC50Impl$DebugVC50SubsectionDirectoryImpl.class': File name too long

In this particular case it appears that heavily nested generated classes are to blame, but also the long basename used by hotspot.

The parts of this path: 1234567890123456789012345678901234567890
   root of repo C:/temp/jprt/P1/B/062752.mbykov/source (38 chars)
   control build adds /build/windows-amd64-fastdebug/hotspot (+38 chars)
   ???? /outputdir (+10 chars)
   Hotspot adds /windows_amd64_compiler2/generated/saclasses (+45 chars)
   Class file name /sun/jvm/hotspot/debugger/win32/coff/COFFFileParser$COFFFileImpl$COFFHeaderImpl$DebugVC50Impl$DebugVC50SubsectionDirectoryImpl.class (+132 chars)


rm: cannot remove `C:/temp/jprt/P1/B/062752.mbykov/source/build/windows-amd64-fastdebug/hotspot/outputdir/windows_amd64_compiler2/generated/saclasses/sun/jvm/hotspot/debugger/win32/coff/COFFFileParser$COFFFileImpl$COFFHeaderImpl$DebugVC50Impl$DebugVC50SubsectionDirectoryImpl.class': File name too long

It would help if any of these paths could be shortened.