[Haskell-cafe] debugging vector index out of range

Hi, I'm getting a vector index out of range. I'm trying to figure out how to get something to give the line number of the offender. However, attempting to use 'ghc -prof' gives me a problem because several of the libraries I'm using don't have profiled versions. Is there some way for me to debug this ? That is some way to debug it without inserting debug traces everywhere checking the vector indices ? Thanks.