Bank scam. Is it or not?

Hi Using both Internet explorer and firefox latest browsers when I log into my bank I get an unusual box appearing in the form of a message from Windows. It says I need to resend the data to display the page properly. I have the option to click ok or cancel. I've clicked cancel and the page displays ok.

Am I being paranoid or is there something wrong with this box? Is it a sign of someone trying to obtain my log in details?

Any advice would be most welcome.

Regards Steve