I read closely the anti String posting and don't remember ever actually seeing an issue being fixed by the removal of String useage.
I had several threads where the change from the String class to using character arrays fixed the problems.
Anyway, I didn't say that the line I posted was posing problems for the OP, that was just the indication that he uses the String class. Because I've seen lots of strange behaviors because of the usage of the String class, that's always the first thing I try to eliminate.