confusing error using .NET C++

[Al Havrilla]

i'm getting the following error from my DEBUG build of a
program that ran fine under vc 6.

---------------------------------

ntdll.dll!77f75a58()
ntdll.dll!77f9cb5e()
ntdll.dll!77f82c95()
KERNEL32.DLL!77e75b6c()
KERNEL32.DLL!77e6c75a()
cs.exe!_CrtIsValidHeapPointer(const void *
pUserData=0x0103f8c8) Line 1807 C
cs.exe!_free_dbg_lk(void * pUserData=0x0103f8c8, int
nBlockUse=1) Line 1132 + 0x9 C
cs.exe!_free_dbg(void * pUserData=0x0103f8c8, int
nBlockUse=1) Line 1070 + 0xd C
cs.exe!operator delete(void * p=0x0103f8c8) Line 369 +
0xb C++
cs.exe!RxPacket<60>::`scalar deleting destructor'() +
0x20 C++
cs.exe!CommPort::releaseWhosThereRxPacket() Line 137 +
0x2b C++
cs.exe!CommPort::waiting_on_whos_there_query() Line 308
C++
cs.exe!CommPort::run() Line 600 C++
cs.exe!CommEngine::commThread(void * pParam=0x00000000)
Line 98 C++
cs.exe!_AfxThreadEntry(void * pParam=0x0012fa8c) Line
114 + 0xd C++
cs.exe!_threadstartex(void * ptd=0x01037558) Line 241 +
0xd C
KERNEL32.DLL!77e7d33b()

----------------------------------

any help would be greatly appreciated. the pointer in
question is "newed" by a worker thread then "deleted" by
the same thread .... so seems to me it should be using
the "local heap".

thanks,
Al