First of all don't use the tuner without AC adapter with passive LNB switches, this will cause that the tuner will try to take all the power from the USB Port.
The settopbox won't allow this with passive LNB switches and they will reconnect the tuner via software.
The AC adapterless mode is only supported with active multiswitches which don't require too much power.
The Settopbox will eject the tuner, and since Enigma2 does not support hotplugging it will crash (this is no problem of the tuner).
Also be sure you are using the latest driver because it includes a workaround for a weird vu+ settopbox bug.
You seem to have another problem as well, however for the other problem we need to check the Enigma2 Logfile.
According to the latest information which you have provided in the Chat everything seems to work.