TetherBerry freezes Blackberry device

I've managed to get TetherBerry to work with only some success.

The main problem I have is that the application freezes the Blackberry and will not open. If I press the "end call" button it unfreezes the blackberry, but the application will not open. If I press alt+back to switch applications, the TetherBerry icon is present, but it will not load the TetherBerry app screen. It's as if the app is unresponsive. I have changed the app settings for TetherBerry to give it full allowances. And I believe that my APN settings are correct because the blackberry browser works fine as well as other apps that utilize my data connection. This problem occurs about 75% of the time.

Please help!

Thanks.