I've had several occurrences of the same problem logging into my work PC
Error when logging in "Unable to load ZENautil.dll"
Only re-imaging the PC seemed to fix the problem and then it would recur.
We eventually traced it to GIMP Portable. There is an article here:
Which says that the problem is due to GIMP Portable renaming c:\windows\system32\xmlparse.dll
Is this a known problem with GIMP Portable? Is there a fix for this?