Can you post some code demonstrating how you can be able to write a file, but yet not be able to delete it? There is no -x permission on an NTFS file. There is such a thing as a "read only" file, but that is not what you are describing.

One reason why you may not be able to delete a file, is that it is currently is use. There are solutions to that. Is that the case?

Update: To "delete" a file that is currently in use, rename it to something else and then delete that file name. Once a file is "opened" and the program has a file handle, that's all that matters. You can prevent new users from opening that file using the "name", but you cannot not stop folks who already have it "open" from continuing to use it with the filehandle.