Hi - I'm running a Slackware 12.0 machine. A recent security update changed PHP from 5.2.3 to 5.3.8. That broke TimeTrex. Apache error log was full of stuff like
bcadd() is a function from the bcmath PHP extension. Its likely that your PHP upgrade caused this extension to no longer be installed or to be disabled.
If you upgrade PHP again, we recommend going through the TimeTrex installer and it will alert you to any issues with PHP without harming your data or settings whatsoever.
TimeTrex works fine with PHP v5.3.X, in fact I'm running PHP v5.3.5 on my test system right now without any problems. So there is something in your upgrade process that is breaking your PHP installation.