What would cause inability to register/unregister DLLs on an Admin account

Question

I've been installing IBM Rational Software on and off for the past couple months - on my computer and a few others around the workplace; and I've never run into a problem like this.

The install files for several products are on a shared drive; when installing them with a FULL ACCESS Network Admin or Local Admin account.. I run into "failed to register X .dll" errors. Some software its only a few DLLs, others its 80+. It seems like some DLLs will register while others will not. Even using Regsvr32 to register them on the command-line fails. The software has been successfully installed in the past on multiple computers, however now this issue has come up on not only my computer but 2 others - both using the same admin access accounts as before.

I suppose its possible there may be file damage on the shared drive where the install files exist, but then why would the only issue during the install/uninstall be the registering/unregistering of DLLs. My only other guess at this so far has been that they are shared/protected DLLs from other Rational software, possibly of newer versions? Of course this may outline my total lack of understanding how Windows houses and manages DLLs.

Answer 1

I think the latter is highly likely, as you will often find that DLL's are compiled against a particular version and newer versions may break these dependancies.

99% of the time in the past I have found this to be the case. I would suggest creating a VM with just the OS, and create snapshot. Then insatll the original software for the Rational software, and ensure that it still works. If it does you will know the problem is with the Rational upgrade. Then upgrade the Rational software and test of the DLL still work. If they do it means the upgrade leaves the originals intact.

Rollback the snapshot and install the new Rational and then the software with the error. This way you can eliminate most problems quickly.

Answer 2

I've sometimes run into the problem that badly-written DLLs wouldn't register as long as Data Execution Prevention (DEP) was on.