Userform object not found after period of inactivity

I'm going to be skimpy on the details here because I have to hurry off but I will add more if necessary.

Put simply, I have a userform activated by an ActiveX button. Click button, form opens, no problem.

I'm finding that when the workbook is open for some time and just sitting there, no changes or edits being made, if I try to click the button and open the userform again, I get an "object not found" message, often followed by a crash. I don't have any other background code running when this happens, although I do usually have one other workbook open.

If anyone has any speculation on why this might be happening, I'd be grateful!

EDIT: I'm running Excel 2007.

In the VB Editor select Tools > options > General > select "Break in Class Module" > Ok
That should enable you to debug when the error occurs, so you can see what is causing the problem.

Thank you for your reply.
It already does allow me to debug, but all that does for me is show that the command (ex. "UserForm1.show") is highlighted. Every time I try to step through the code, it gives me the same message, that the object can't be found. I also notice that when I go into VBA to try and open the userform to figure out what's wrong, despite that it shows on the list, I get a similar error (and then sometimes Excel just crashes because screw you).
(For the record, the form isn't actually called UserForm1, and as I said, the code normally does work just fine, I was just using that as an example).

Upload a copy of your workbook.
Remove sensitive data.
It make life simpler, rather than 'crystal ball gazing'.
torachan.

You could attach your sample workbook.
Click on GO ADVANCED and then scroll down to Manage Attachments to open the upload window.
(Don’t use the paper clip icon to attach your file, it doesn’t work.)

Thank you for the tip, didn't even see that.

I would love to, but I'm sad to say the file (sitting at about 15mb) is too large. If you really need me to, I'll go through and dig out all the sound references to reduce the file size/not need to upload the sound library, but would you mind trying the link I posted first?

I have downloaded your file.
Still trying to replicate your problem.
No luck so far, will continue in the hope of failure.
torachan.

Thank you for your efforts.
I'm starting to think that this is more of an Excel problem on my computer than a specific workbook problem. I've been noticing that Excel will crash after it has been idle for too long, regardless of whether this workbook is open or not. So I'm thinking that the issue is with Excel itself.
I've done a repair, and uninstall/reinstall, and I'm not sure what else to try. But I'd like to know what's causing the problem in the first place, because it makes very little sense to me.

So this is just an update because I solved the problem. There must have been something wrong with my installation of Excel 2007, because I got Office 365 and.. no more problems. Sigh.