I uninstalled BB Messenger to free up some app space and when I receive a text I can't open it. It gives me error of uncaught exception:java.lang.Null pointer Exception.

I re-installed BB messenger and I am able to read my texts now.

Is there a way to delete BB Msgr so I can free up app space without it effecting my SMS texts?

I think if you have the BB Messenger contacts linked to your contact database, they show up there.
Try the Remove Contact Link option, and I bet it will work fine.