It'd be really nice if you could put together a self-contained full runnable example of the problem. That said, these types of problems are often hard to boil down. Also, if you're using perl < 5.8, I'd suggest trying >= 5.8.0 - it has fixed internal-to-perl memory problems for me, this may be another area that has been beefed up between 5.6 and 5.8.