Interesting it is indeed there, its very odd that I've never run across it before. Tracking back the code it doesn't look like its actually check for browser versions, the code that triggers the error is in the app.js:
// check browser
if (!bw.dom || !bw.xmlhttp_test() || (bw.mz && bw.vendver < 1.9)) {
this.goto_url('error', '_code=0x199');
return;
}
There are three checks, first "!bw.dom" That checks a variable in the common.js file which checks for the ability to select an element by id.
this.dom = document.getElementById ? true : false;
The second check "!bw.xmlhttp_test()" calls the xmlhttp_test() function also in the common.js file to check for XMLHTTP support.
// test for XMLHTTP support
this.xmlhttp_test = function()
{
var activeX_test = new Function("try{var o=new ActiveXObject('Microsoft.XMLHTTP');return true;}catch(err){return false;}");
this.xmlhttp = (window.XMLHttpRequest || (window.ActiveXObject && activeX_test()));
return this.xmlhttp;
};
The third check "(bw.mz && bw.vendver < 1.9)" checks if you are running Mozilla and that the version is less than 1.9.
I'm not sure which check is causing it to break for you though, what browser are you using?