Perl out of memory [sbrk()]

[Per olof Ljungmark]

I'm running imapsync that also uses p5-Mail-IMAPClient-2.2.9 to transfer 
mailboxes between imap servers.

The following error occurs when a message has an attachment of more that 
approx 35MB in size:
"Out of memory during "large" request for 67112960 bytes, total sbrk() 
is 487512064 bytes at /usr/local/bin/imapsync line 790."

Running 5.3-STABLE a week or so old
Perl 5.8.6 from ports.

What bothers me especially is that this error will not occur when I run 
the same command from a old RH Linux (7.2) box. Appriciate comments 
and/or hints.
Thanks,