MLPowSim MLwiN macro error

[KateBest]

Hello,

I'm trying to use MLPowSim to produce a sample size calculation for a 2-level logistic regression. When I run the simu.txt macro, I am receiving the following error: 'error while obeying batch file analyse.txt at line number 5: LOOP b51 1 b21 1. Upper limit must be >= 0'
Atm I have specified no explanatory variables, just a random effect with 32 units at the second level.

What does this error mean?

Thank you for your help,
Kate

[ChrisCharlton]

Are you able to provide a list of all of the inputs that you entered into MLPowSim so that we can attempt to replicate this?