Command button in Word, defaults to design view

Hi all.

I've created a word document with a command button in it which opens "disk cleanup", and it works fine for me. Unfortunately it's not working for users! They are accessing the document via a weblink and when it opens it seems to be defaulting to 'design mode', meaning when they click on the button it opens up the code, rather than executing the action.

Does anyone know a workaround for this? I've tried looking for some sort of "default to normal mode" script without luck .

Thanks.