"Virtual Reservation" presumably refers to the idea that in Windows, you can "reserve" (claim) a range of virtual addresses, without actually allocating physical memory.
e.g., from http://msdn.microsoft.com/en-us/library/windows/desktop/aa366887(v=vs.85).aspx
MEM_RESERVE 0x00002000 Reserves a range of the process's virtual address space without allocating any actual physical storage in memory or in the paging file on disk.
So, presumably something in TestDLL.dll called VirtualAlloc, and there was never a corresponding call to VirtualFree. You'd have to include more information about TestDLL for the investigation to proceed further.