How do I take away _bx

Some of the modules I installed show up as _bx_polls for example, how do I get rid of this?

That is normally an indication of a missing language key. Which should not happen unless your running a different language and have not translated the english keys into the other language file.

Are you running with a different language other than the default en that comes with dolphin?

Deano is right but there is another possibility.

That happens when you just installed the module. Try to refresh the page or open another link of the Admin Panel and go back to the Modules list, the _bx_xxx is now gone and replaced with the name of the module ;-)