When changing the print setup printer on a report parameter to a new physical printer, and attempting to preview or print, we receive the error : Error: File C:\Program Files[X86]\Blackbaud\The Financial Edge\Rpt\GL***L.rpt: Invalid printer specified. 
We are currently investigating this issue and will update this article.
Steps to Duplicate
1. Go to Gl, Reports. Open any report parameter. 2. Go to File > Print Setup and change the current printer to another physical printer and click ok. 3. Click Preview, the report will attempt to run then show the error message.