Thickbox from flash in IE doesn't work all the time?

Hi all,

I am using to open up thickbox from flash.

Now i works in firefox but in IE it doesn’t work all the time. I am calling tb_special link from a xml file which i read in a html textfield like

<a href="javascript:TB_special(\'publications/special.jpg?keepThis=true&TB_iframe=true&height=500&width=750\')" >test</a>

When navigating the website and trying the thickbox a second or thrid time it doesn’t work anymore?

I notice in firebug the following errors, could these cause the problem in IE???

url.indexOf is not a function
tb_show("", "publications/special.jpg", false)thickbox.js (line(256)
TB_special("publications/special.jpg")thickbox.js (line(19)

[Break on this error] if(!params['modal']){

Any tips??