JS error on the first time load for page containing FCK edit

Hi everyone

I have implemented FCK editor on a light-box based floating div in .ascx file (ASP.NET) and the editor is hidden by default on the page load. Hence when an end-user double clicks on a given div the FCK editor opens up on the light-box pop-up window (which is basically a floating div). However when end-users arrive on the page (containing the editor) for the first time, they encounter the following Javascript error:
Error : Unspecified Error
URL : ../fckeditor/editor/fckeditor.html?InstanceName=someName&ToolBar=Default.

But when they double click on the div the error is gone and even when they post back on the same page.

Would be really great if any one my friends could come up with the cause as to why this problem occurs and a effective solution to eradicate the same

Regards
Nishant