Since the Storm was released there have been problems using Tiggit Mail on the Storm and the Storm 2. In short under certain configurations, the Storm (2) will crash unexpectedly, possibly several times a day.
Storm users may recall that earlier versions of the RIM OS had problems that caused the Storm to crash, but the OS is now much more stable. Regardless of this, tiggit mail (until now) causes the Storm to crash when it is used.
I have just posted a new version of tiggit mail 18.104.22.168 that appears to fix the Storm crash problem. Existing users can download simply by selecting Update from the settings menu, or buy using their BlackBerry browser to go here