7.4.2 out of memory

All,
After I upgraded postgres from 7.3.4 to 7.4.2, one of my program got following error:
DRROR:    out of memory
DETAIL:    Fail on request of size 92.

any idea??
does memory management have big difference between 7.3.4 and 7.4.2???
this program using a chunk of share memory and a lot of temp tables.


Thanks.



Jie Liang