Enty point not found error

I'm running a Gateway laptop with Vista Home Premium edition installed.

I keep getting the following error during startup:

LOGONUI.exe - entry point not found ~~ The procedure entry point line
TranslateAddressW could not be located in the dynamic link library TAPI32.dll.

After Windows starts, I get the following.

Webroot SpySweeperUI.exe - entry point not found ~~ The procedure entry
point line TranslateAddressW could not be located in the dynamic link library
TAPI32.dll.

Finally, I get the same message when I start IE7:

IEUSER.exe - entry point not found ~~ The procedure entry point line
TranslateAddressW could not be located in the dynamic link library TAPI32.dll.


I ran ProgramChecker and found that I have the following version of
TAPI32.dll:

Name: tapi32.dll
Version: 6.0.6000.16386
Location: C:\Windows\System32\tapi32.dll
Hash: F02C254B9135ADEAD1095F7153B6560F

It looks like the wrong version of TAPI32.dll somehow got installed, since
the installed version has the wrong hash.

I tried system restore without success, so I'd like to know if there's a way
I can reinstall TAPI32.dll without reinstalling Vista.

Thanks.