Who's your service provider?
There have been a lot of threads on Verizon RAZRs and their inability to synch with iCal, so a quick search should turn up some useful information. Most simply, Verizon has crippled the phone -- feel fortunate you can back up your address book without a firmware flash!
If you're not using Verizon, a "V3C + service provider" search should pull up some relevant information.