Okay, I placed the iframe as first element in the body of the page, and it works.

 

So apparently, depending on where I place the iframe on the page, I get this strange "oxae is null" error, disabling the browse button.

Weird thing is that neither on google, I find any info on this error.

 

Oh well, I'll puzzle around some more with the html elements, should find a solution that works.

 

Thanks