I have squid version 2.6 running on ubuntu linux as a proxycache although caching is not being used, the problem I have is that certain websites that require the user to log into do not seem to pass through the squid, the only thing I see is that the website is trying to access a file called tlogin.php any suggestions would be appreciated.
That's right. You normally don't want proxycaching to cache password-protected pages, because then the password-protection would be lost.
I think a work-around is to have a SQUID server inside the password-protected area, so that this content is cached. But I've never tried anything like that.