It's a known issue on windows. I wasn't able to fix what was going wrong with the allegro4 dialogs there--it's a mystery really-- but there's now 2 places in the config file where you can fix it:
Set one of the screensaveer values - "ss_enable = 0;" or the completely arbitrary "ss_rate" to 4 (I think it's 4..?). There's also the screen saver option in the dropdown menu in ZC; simply set this to 'never'. (You only need to change one of them for it to work, any one will do)
