This is likely caused by the Course Library being deleted or restored from a database that did not contain the actual course(s) played by the golfers being transfered. The steps listed below should correct this problem.
1. Insure the courses last year's league played are in the Course Library. If they're not there add them.
2. Launch LM and open last year's league.
3. Click Setup > Automatic Scheduling... and click the <Build / Optimize Automatic Schedule> button.
4. Select last year's course that was played and click the <OK> button. Click <OK>, <Finished>, and <Close>.
5. Click Tools > Transfer players between leagues... and transfer your players/info from last year's league to this year's league