It sounds like you might be trying to install multiple licenses at the same time (or really one after another). If so, this is not the correct way to do it. I would recommend uninstalling the options with :SYSTem:OPTion:UNINSTall, then install a single key that includes both the 300MHz bandwidth and all options together. I think its the 'DSHH' one, though could be wrong on that. But to be clear, on the DS2000A scopes (as well as all Rigol scopes that I'm aware of), you only enter a single license key (that enables all options). And it doesn't matter if you send the license key over Ultra Sigma or RigolBildschirmkopie, both are doing the same exact thing.
Edit2: Interesting, I just checked the documentation from when I liberated my DS2000A and the code I used was 'NS8H', which was labelled 'All options, bandwidth 300MHz'. This was with rigup-0.4. Maybe try that if the other doesn't work.