Sim card invalid. what do i do (balck beery pearl 8100)

It's means your phone still locked for particular network, you must unlock it with blackberry pearl 8100 unlock code. To get blackberry unlock code you can purchase from third party sites on internet, please remember don't try to use free unlock code since it's can damaged your phone.

If your says Sim card Not valid (Invalid Sim) or Sim Error means...it may locked to some Network....You need to Unlock the Mobile to fix this Problem...then GSM network locked means it can be Unlocked,if the Mobile locked to CDMA Network means it cannot be Unlock...You can get the unlock code at reliable cost here http://www.theunlockarena.com/blackberry-pearl-8100/rs13wp9/ and Unlock it from the GSM Network lock...Then You cannot get the Sim error or Not valid Sim error while inserting other GSM Sim Car

Your BlackBerry need to be unlocked .

It's a full detailled guide on how to unlock your BlackBerry .
please read it carefully .

1. Insert any sim card
2. Turn off all of the wireless connections
3. Go to Options
4. Select Advanced Options
5. Select SIM Card
6. Hit menu select show keyboard (where needed)
7. Type MEPD (you will not be able to see the typed info)
8. Type MEP2
9. Now it will say enter network mep code
10. Enter Unlock Code

All done. I suggest you by the unlock code from a fast and reliable codes seller such as blackberrymep.com .

It needs an unlock code. you may have to purchase one or ask your provider for one. the procedure on how to enter it and where to purchase it can be found here.