Right-click and search for a string in a file?

Hi all, I have some programs that spit out a .log file. I'm wanting to be able to right-click on a .log file and go to "Check for Errors" or something like that. I need a script that will check the file I right-click on and looks for "ERROR", "WARNING", and "uninit" strings in the file. I've found some programs that will do this, but A) they cost money, and B) they seem to only allow up to 2 search strings where I need at least these 3. Can anyone start me out on a script to do it, and then how I can pass the file name into it from the right-click? Thanks!

Edit:
I'm currently using "find "ERROR:" <filename> > <output file>" but everything is hardcoded. I also need 3 of these but want all listings to show up in one window.

Okay, possibly nevermind. I'm doing this:
FINDSTR "ERROR WARNING uninit" %1
pause


and it's doing a pretty good job...any other suggestions?