InfoPath Dev

Currently am storing infopath form in document library with current date as filename. I want to show error message (popup) when user tries to submit form on same date(need to validate for duplicate filename).

1. Add a data connection to your form that receives data from the document library where you are submitting your form.
• Make sure that this receive data is set to not connect on load
2. Add a Form Load rule to your form with the following actions: 
• First add an action to set the value query field for the title to the current date: today()
• Add an action to query the data connection
3. Add another rule after the one in step 2 that compare the data field in the query data connection
• The condition should check to see if it exists or is non-blank
• If so, you can display a dialog popup (filler only) or switch to a view telling the user the form already exists (and give them a link to the form to open it)