MkDir command fails on some Windows 7

We have some legacy VB6 code that uses the VB6 command MkDir to create folders as required. This functionality has been working well for many years. Recently we are getting reports from customers that the MkDir function is failing on some Windows 7 Enterprise PC's with an error message of 'Warning number: 75 Path/File access error'.

We have created a simple vb6 test app that uses MkDir and tested it in one organisation on their Windows 7 Enterprise PC's (not all PC's created from same SOE/Image) in creating folders under the %TEMP%' path (e.g 'C:\Users\xxxxx\AppData\Local\Temp') and this is what we have found:
- On some machines this works fine for a nominated user
- On other machines, logged in as the same user, this fails with error 75
- On the machines that this fails in VB6 code, the user can create the same folders using windows explorer
- We can see no differences in the folder permissions on machines that work to those that fail
- It does not matter if it is a physical machine or a vm
- If we perform the same operation in vb6 code using the FSO (File System Object) instead on MkDir it works on all test machines (including those that fail with MkDir)
- Running the VB6 code as Administrator or in compatibility mode does not resolve the issue.

Our tests suggest that the VB6 command MkDir has some issues on some Windows 7 Enterprise pc's.

Does anyone have any other knowledge of this issue or any suggestions on how we may configure the Windows 7 Enterprise pc's to always work with the vb6 command MkDir?

Thank you.