popups module not working

hi,
i have used popups api module to have a popup window. When user clicks on 'Contact us' he/she should get the contact us page popup. It is working fine in my system , problem is that it works only when i am loggedin, it is not working for any other user or anonymous and it is not working even if another user with same permissions, just a white screen is displayed.
I have tried to give permissions but in vain, i found no option for this module in permissions page also. I think somewhere the javascript is getting clash..Please help me fixing this issue...

Thanks in advance