Imported scheduled reports from 3.1 to 4.1 can fail with the following message:
Unable to connect. incorrect log on parameters. Details: [Database Vendor Code: 1045]
Sometimes there can be issues migrating reports from 3.1 to 4.1
Use the details from the old saved report to recreate a new scheduled report. When created, choose "Run Now" to test the report
If this still doesn't work , you should open a Support Ticket.