Interpretting UMDH output

I have an application that is leaking memory under a load condition.  Under 
a
light load condition the app does not leak(stays around 4M).  The app's
MemUsage as displayed by TaskManager starts out about 4M and in the leak
condition can grow to 50M.  If the load is removed, then the MemUsage slows
reduces back to the base line (4M) MemUsage size.

I tried using BoundsChecked to determine what was going on, but this did not
help.

I then tried UMDH and this shows some results that I do not understand.  As
I understand it UMDH dumps heap allocations and shows the calling code the
caused the heap allocation.  In this case the offending code is not called
from my code.  How do I interpret this result and what do I do about it?
What does this heap allocation indicate?

*- - - - - - - - - - Heap 00690000 Hogs - - - - - - - - - -

0053AA4A bytes in 0x12d5d allocations (@ 0x00000028 + 0x002493C2) by:
BackTrace00091
ntdll!RtlDebugAllocateHeap+000000FD
ntdll!RtlAllocateHeapSlowly+0000005A
ntdll!RtlAllocateHeap+00000954
MSVCRT!_heap_alloc+000000EB


00093A90 bytes in 0x1dfa allocations (@ 0x00000028 + 0x00048B80) by:
BackTrace00242
ntdll!RtlDebugAllocateHeap+000000FD
ntdll!RtlAllocateHeapSlowly+0000005A
ntdll!RtlAllocateHeap+00000954
MSVCRT!_heap_alloc+000000EB
MSVCRT!_nh_malloc+00000010

mark

p.s. Is there a more approrpiate newsgroup for this type of posting?  I
apologize if this is not the correct news group.