Object library invalid or contains references to object definitions that could not be foun

Hello!
First post here!

I've got a sheet with several ActiveX form objects. When I open the workbook the ActiveX objects works just fine. But after some time playing with them, they stop working. Nothing happens and I get the error "Object library invalid or contains references to object definitions that could not be found."

I've tried to delete the .exd files but once I start Excel again, they reappear. And nothing changes. I'm able to play around with the objects, clicking on them, changing their values. Then after a while they stop working again. If I restart Excel, they always work. But only for a small period of time, then they stop working.

The sheet contains a few different ActiveX objects.
It's basically a date picker which allows you to see data between two dates. You choose two dates using comboboxes, you then press a button and checkboxes are created. The amount depends on the dates you choose. Everytime you press the button, the checkboxes are deleted and new ones are created. You then select some checkboxes and press another button to show the selected data.

Not sure what to do. Anyone knows why this might be?

/Jens

*Edit*
Attached the excel document. It's in Swedish but go to the sheet, "GrafVal". There's the date picker. Choose two dates and press "Visa anställda i valt datumområde" (Show employers in the chosen date region) Then the checkboxes will show up. If you choose two other dates and press the button, other checkboxes are shown.

I changed the names of the employees btw. The real employees have Swedish names. The data also consists of random numbers.

More progress! I'm noticing that it's the "Visa anställda i valt datumområde" - button that's causing the problem. I can play around with the date picker for how long as I want. No problem there. But when I press that button a few times, the error happens. And all the ActiveX objects stop working!

Could it be the deleting and creating of those checkboxes that's causing the problem? Like somehow something builds up? Like they don't get totally removed?