Error 75 File/Path access error, sometimes Error 1004

I have been making a large-ish userform project over the last 2 weeks. Something is causing a fatal error about every 15 minutes. Most of the time the code executes smoothly, but SOMETIMES when I execute a procedure or save the workbook, I get either Error 75 File/Path access error or Error 1004 Object not Found. When debugging is possible, userform.show is highlighted. But if the error comes on the save event (autosave included), excel just crashes.

I have tried to get in the habit of saving the workbook every time I do anything, but this is really getting more frequent and it's getting under my skin. I've found several other people having similar issues on other forums, but no real answers. I have read that MS Query may have a memory leak or that perhaps it could be caused by how I am loading the combo boxes in the listform. But I would guess that such an error would throw EVERY time, not only some of the time.

So far I have debugged my code and copied my entire project into a new workbook, a version of which is attached. Please open the workbook and fool with it - open the userforms and change the combo boxes, etc for a while with the VBA editor open (while you're at it feel free to look over my code for what might be causing the error..) It will crash eventually.

PS - several places I have put pieces of ADO code. for obvious reasons I have changed the server path to \\server\quotes1.accdb - so i have also attached an empty file called quotes1.accdb, which you can save to your desktop and modify those references to make the whole code work for you.

Nothing?

@Colin: Thank you for the suggestion. I'll try that and we'll see if it works.
@romperstomper: I had to put SOMETHING to bump the topic

Colin,
I was hoping your solution would work, but alas it has not. I have continued getting the path/file access error at times when I am initializing a form or saving the workbook.

In the meantime I managed to put in some code to set all the object variables to nothing at the end of the procedures that use object variables, in hopes that there would be a memory leak somewhere that I could plug. That doesn't seem to have helped either.

Anybody got another idea?

Great...

When I run the Code Cleaner I get:

"Microsoft Office Excel has encountered a problem and needs to close. We are sorry for the inconvenience."

No error number, no debug, just close. Obviously the Code Cleaner has found the error and is stepping all over it :P

How would one get around THAT? Can you try on your computer, using the attachment?

Hmmm I have already done this once with a totally fresh workbook.

@romperstomper: I was not aware of that. Are you saying the references will "turn on" automatically when the code is run on a random user's machine?? If so, I'll go ahead and take that code out (although I am pretty sure that isn't causing the error).

Well, I have run the code and tested the workbook on two other machines, and those machines did not experience the same crash phenomenon that I have been experiencing. This leads me to believe the error has arisen from my copy of Office 2007. I have repaired it (1 "setup" repair was found and completed) but I'm requesting our IT department to do a full re-install just in case.

I will keep you posted.