Poor diagnostics on invalid file names

[tim-caper]

Preamble: multiplatform install prepared on Linux and one group contains files with <> characters in their names. Naturally, such files can not be created on Windows.
During Windows install dialog appears with the message 'An error occurred during install.'

1. There is no hint what the error is. Something like 'Can not created file ' would be quite helpful, including system error message yet more helpful.
2. The Finish screen claims that the tool was successfully installed!

InstallJammer 1.2.15, install built under RedHat Linux, tested on Windows XP.