Error in um_fcst

I am getting the following error:
Error code: 4
? Error from routine: STWORK
? Error message: STWORK: Number of fields exceeds reserved headers for unit 11
? Error from processor: 344
? Error number: 50
Please advice. Thanks.
Suite - u-db324
Username- aurocumulus

The issue is discussed here 6. Further Exercises (1) — NCAS Unified Model Introduction

I recommend that you work through this training material at least before running UM suites.