You don't want to disable DEP; you want to modify your app to work within it.
Per http://msdn.microsoft.com/en-us/library/windows/desktop/aa366553%28v=vs.85%29.aspx
If your application must run code from a memory page, it must allocate and set the proper
virtual memory protection attributes. The allocated memory must be marked PAGE_EXECUTE,
PAGE_EXECUTE_READ, PAGE_EXECUTE_READWRITE, or PAGE_EXECUTE_WRITECOPY when allocating memory.
Follow these simple directions and your code can coexist with DEP.