Are you trying to open a project with the xml extension in BAS? Probably your project is damaged, you did not edit it manually using text editors? Try to restore it from backups located here:
C:\Users\User\AppData\Roaming\BrowserAutomationStudio\projectbackups
If your cookies in same format as BAS, you just read it from file to variable and go Network-load cookies-set cookies for browser. If format of your cookies not compatible with BAS, compare and convert all your cookies in right format