Createfile file name error

We have a "simple" call to CreateFile:
flashfileHandle=CreateFile((LPCWSTR)working_path,FILE_READ_DATA|FILE_WRITE_DATA,0,NULL,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,NULL);
which apparently had been working in Vista (32 bit) up to a few weeks ago. Now it is failing in our user's systems. It is still working properly in XP. Apparently this is related to some update that Microsoft did with an automatic update.
The return is either error 2(FILE NOT FOUND) or 123 (Invalid Name).

This code is in a "terminal module" compiled and linked under Visual studio 2005 SP1 with the test being done at command line level.

Using exactly the same name (working_path) in fopen_s works.
I have tried to set the administration rights to administrator and turning "user accounts->turn user account control on or off" off with no effect.
Eliminating FILE_WRITE_DATA does not help.
Any idea what has happened and how to fix it?

It seems that lately everything needs "elevated privileges" or "run as administrator" to work properly.

This condition is set in the file properties of the program you are running. It is a checkbox on the compatibility tab.

Jim,
Unfortunately, we already tried setting the application compatibility permissions to "administrator" with the check box. We also tried running it in XP compatibility mode. It was a significant surprise that even that didn't work.

The problem has been solved. It was that the path being sent to CreatFile (which is a long character string of unicode) was invalid but XP and the earlier updates to Vista had been tolerating it and doing the intended file operation. With the update in Vista, the string was no longer tollerated.