Is this a known problem in Netbanx payment module?

[GerryTheMole]

I am using 1.3.8a and at the moment don't have time to do the testing to move to 1.3.9. However we are using Netbanx payment module which has been supplied by Netbanx. If used properly there is no issue but if you process an order successfully and then try to process a second with an error or by cancelling from Netbanx it then reports a successful transaction.

Netbanx say that this is a known problem with Zen Cart. They say "This is unfortunately an issue with Zen Cart's own session keeping"

Is there a fix for this please?

[GerryTheMole]

It appears there is a session variable - Netbanx's variable - that is set with the reference if successful, but as a session variable it remains set until overwritten. If you try a second session and this fails then it still reports successful. It LOOKS to me like the netbanx.php program should set this to null before passing control to Netbanx.

BUT..

Everything I try is failing. This is the current state. If I FTP the working version to my Windows Vista laptop as a binary (start size 8524) is then shows a size of 8524 on windows. I the rename the server version so as not to overwrite and then FTP back again as binary ending at 8524. I then go into modules, payment on the control panel and it no longer works correctly - it stops at Netbanx and doesn't show the right hand properties panel. I then delete the 'new' version and rename the original back and everything works.

Is there some version of date checking against the source files because it's the only thing I can see has changed?

Suggestions please?