Exception in sforce.apex.execute (which is in try catch), and page doesn't accept inputs further

I have a script which calls apex function through “sforce.apex.execute”. It is in try catch block and I have an alert in catch and return statement after it. If there is an exception, I get the alert message however if I correct data on page and again click button which calls this method, it doesn’t take the corrected data but takes the old data and gives the exception again.

Any pointers would be of great help.

Thanks!!