Just to follow up and give some closure to my original post: a pin was broken off inside the charging slot on my wife's Pearl. Why it charged fine on our laptop and nowhere else I have no idea. But SunCom swapped it out under warranty for a brand new unit, so all is well. It took about two weeks to get the new phone because they had to ship the old one to RIM, but in the meantime they gave her a loaner Pearl so she was able to have access to all the features she was used to while waiting on the new unit.
This was a pretty good customer service experience with SunCom.