Another candidate also came across this problem and has proposed this fix for the error:
This error is most probably due to clock format error. Some websites still use US format for coding hence if your clock is set as Indian format then the error will be shown.
How to change the format?
Go to Control Panel --> Clock, language and region --> Change date, time....format --> Select for English US
Start your browser and go to the official website allindiabarexamination.com and log in to the admit card page now.
Did it work now?