This quote from Vinod on the aolserver listserv might help:
...AOLserver from CVS from the tip of the aolserver_v40_bp branch.. has this change in it:
http://cvs.sourceforge.net/viewcvs.py/aolserver/aolserver/nsd/driver.c?r1=1.17&r2=1.17.2.1
It basically adds a parameter 'maxinput' inside
ns/server/${servername}/module/nssock. The default of this parameter is 1 MB, so uploads above that size silently fail.
Otherwise, you might check at aolserver.com (and post your findings here for others, please.)
cheers,
Torben