I had PDFCreator installed in my Vista computer, when it stopped working I uninstalled and tried to reinstalled but it gave an error message as given in the link below.

I tried the following to resolve the issue but could not.
1. Logged into true admin user.
2. Disabled all the security applications.
3. Uninstalled using Revo uninstaller and deleted all the pdf creator files and folder.
4. Reinstalled it but while installing the error came again and was not able to print as pdf from any application.
5. In C>Program Files>PDFCreator> the PDFCreator.exe file does not give the option to add as admin.

The access issue is only with this application.

Does any one know how to resolve this issue?

I had already tried that, it does not work. It gives the same error and it is only for the PDFCreator folder. After I uninstalled this application when I tried to delete its folder in "Program files" it gave access denied error. So, I had to log into Ubuntu (I have dual boot ie Vista+Ubuntu) and then delete the folder.
What puzzles me is it was working fine without any issue and I was able to print as .pdf file from any application. All of sudden it stopped and never worked after that.

Any other idea?

If you can't it to work, get doPDF. It does the same thing. I have both, but I actually prefer doPDF.

I uninstalled ThreatFire and the PDFCreator started working as before. So, the access denied error was because of the ThreatFire. It took some time to find the culprit!!

Yes, I think so, but I don't remember. One thing that I learnt is that if the wrong button is clicked in ThreatFire, then it is very difficult to get back to normal. There was two associated files of PDFCreator in the quarantined tab and only one gave the option to restore and for the other there was no option.
I manually tried to add the exception and it did not work. For testing purpose I removed ThreatFire and without even restarting the computer
PDFCreator started working as before.