rspangl's declare:
Code:
Declare Sub CopyMem Lib "kernel32" Alias "RtlMoveMemory" (lpdest As Any, lpsrc As Any, ByVal length As Long)
Megatron's declare (and the one I use too):
Code:
Declare Sub CopyMemory Lib "kernel32.dll" Alias "RtlMoveMemory" (dest As Any, src As Any, ByVal length As Long)

The actual problem is in the call to CopyMem. Now I have not run this code, just read through it and I am not familiar with the API's in use. But it seems to me that:

Code:
CopyMem p_atypExplicitAccess(0), ByVal p_lngListExplicitEntries, Len(p_atypExplicitAccess(0)) * p_lngCountExplicitEntries
is intended to copy array elements from a block of memory pointed at by the value contained in p_lngListExplicitEntries into the VB array starting at the memory address of p_atypExplicitAccess(0).

This looks reasonable to me. I assume that the values of p_lngCountExplicitEntries and p_lngListExplicitEntries are being set by GetExplicitEntriesFromAcl correctly? I am not familiar with your calling convention to GetExplicitEntriesFromAcl so I assume it is the same as:

Code:
p_lngRtn = GetExplicitEntriesFromAcl(
p_lngPtrDACL, p_lngCountExplicitEntries, p_lngListExplicitEntries)
So I am left to conclude that the error is more to do with what GetExplicitEntriesFromAcl is returning. I will check the MFC for GetExplicitEntriesFromAcl and see what my interpretation of the declare should be.

Cheers