First you need to make sure you can PIM yourself and that you have at least 2 signal bars. Whether you are on a company BES or outside exchange hosting confirm the email address and password you should be using when activating. Did you let the IT people know you are using a storm because the XML file needs to updated on the BES to support new devices.
The last step is to have the BES administrators remove your BES account and re-add you, that fixes activation issues 75% of the time..the other 25% would require a BES reboot! LOL!

Later and good luck