Java web application will not run on iMac.

I have a problem that has defied technical support in 2 organisations.

I am a stock trader and use a high spec iMac for my trading platforms. Recently I tried to run two different trading platforms on my Mac without success. The applications are Thinkorswim from TD Ameritrade and Trader Workstation from Interactive Brokers. I can download the Mac versions of either the web based or standalone versions of these apps and install them ok but when I double click the apps I get a "bouncing" logo appear in the dock and then it disappears. These are Java based applications. I have checked that Java is enabled, latest version etc and that Java web start is in place - but to no avail.

Now the weird part, I also have a Macbook Pro and the apps load OK on this.

Both machines run latest version of Lion, and all parameters and settings for browser, Java, preferences are identical. I cannot find a difference between the two machines.

Can anyone suggest a possible cause and solution? Greatly appreciated.

Des Cahill

Kildare

Ireland.