During my installation of a screen capture application named Snagit, the setup asked me to provide two DLL’s (unidrv.dll and unidrvui.dll). I searched for them in two directories c:\windows\inf and c:\windows\system32\drivers. In both directories the files were not available.
The installation of the application was successful. After a reboot it started showing messages that the application printer was not installed. I uninstall the application and I started again but now with some tips where to find the missing files.
If you encounter that these files are missing please follow my guides below:
Start “Command Prompt” and type dir unidrv*.dll /s to search for these files. I was lucky and I found mine hidden somewhere (C:\WINDOWS\system32\spool\drivers\w32x86) on the hard disk .
If you can’t find the files than open the following file if available C:\WINDOWS\Driver Cache\i386\sp2.cab and extract the two DLL’s.
This fixed my problem and without downloading un-trusted DLL’s from the Internet. You can search for these files but be sure what you are downloading from the web.

david
For Windows Vista Home Premium 64BIT I found it under C:\Windows\system32\spool\drivers\x64\3
Thanks for the help