After review of archived discussion on this error, I'm opening this thread to ask for help on NXT-G 2.1 error code 1003.
This error suddenly presented on all attempts to download programs to the robot from the team computer, PC, Windows 7.
What we tried and got the error every time:
1. prior versions of successful programs;
2. new program with only a move block;
3. checked Mindstorms available updates to software and firmware; none found of any sort more recent than our last updates and we have had no problem with this error for quite a while since any updates in the past;
4. complete uninstall of the NXT-G program and restart of the computer;
5. attempt to download to different NXT 'bots;
No problem with this error when:
copying programs that generate this error code to a zip drive and opening them (bravely) on a different computer with the same op system and update status.