Java Error

I’m attempting to access a Bank’s Trading Demo site & at the final hurdle encounter this error message :
10021
Initialization Failed
netscape.javascript.JSException: null

I’m running XP/SP2, have pop ups allowed….current Java version: 1.4.2_06 (buildb03)….any thoughts? or possible cross checks I can perform?….this glitch even has the site techie guy’s scratching their heads!!