What you are describing looks like an old Install Shield bug I've seen
on XP. You should be able to extract the .exe download file using
Winzip (I used 7zip) into a temp folder. Don't worry about it being
a .exe file, Winzip should be able to extract it. The Install Shield
bug is in the extraction portion of the install process so using an
extraction tool like Winzip or 7zip is the only way I've been able to
get around it.
Once extracted into the temp directory execute the setup.exe to start
the actual installation program.