There were many small bugs in .42 OS. I would highly recommend upgrading to at least .64 and would even suggest upgrading to Cingular's .71 (package version .88). There are many links on the forums for instructions on upgrading. You can find the latest OS version for most of the BB models here:
For TMo's OS version try this:
If you get a message about the site being too busy, just hit refresh until it lets you in. It's a known problem with TMo's website right now.