I've had this conversation with the developer before regarding 64bit vs 32bit and lsws webserve is concerned. From what I remember:
1) 64bit for litespeed doesn't help. Lsws barely use any ram and 64bit system induces higher cpu cache miss penaties (2x).
2) There was not much performance difference at all.
Lsws is about I/O performance and that's one thing 64bit anything would not help at all.
There is no reason lsws should not run though with 32bit compat libs though and I remember others have done the same on 64bit distros.