Thats a very strange error, I've not seen it nor can I produce it nor would I expect to.
The reason I say its strange is because that is a "Classic ASP" error not an ASP.NET error. mojoPortal is written in ASP.NET and has no classic asp involved in it.
When I google the error "Active Server Pages, ASP 0138 (0x80004005)" it all about Classic ASP.
When I look at the ClientScript/greybox/loader_frame.html, line 10
I see javascript:
<script>
var GB = parent.GB_CURRENT;
document.write('<script type="text/javascript" src="AJS.js"><\/script>');
if(GB.use_fx) {
document.write('<script type="text/javascript" src="AJS_fx.js"><\/script>');
}
</script>
but the error is like your machine is treating this as server side script (Classic ASP) rather than client side javascript.
I might try changing the opening <script> to <script type="text/javascript"> and see if it makes any difference.
Hope it helps,
Joe