Custom Form hangs if more than one user is using the form at the same time

Hi All,

We have developed a custom form to enter invoices in AR. We have a button Validate, which validates all the records in the form. Now if 2 users are using the form at the same time, and one of the user clicks Validate, the form will hang and user will have to re-login to Oracle application. We are calling a package(via concurrent program) when the validate button is clicked and the popup message is displayed showing in process. This message will be displayed till the background concurrent program is not completed. When the form is open on any other machine,