It could be that the transponder parameters need to be updated in the datafile you are using.
Go to
SatHawk 4000 Datafile Software Download section
Use Satmeter 3.0.2 to open the latest datafile (i.e. V2.2)
Check your satellite on the list. Just change the Transnpoder data (freq, Sr, Polarity, and FEC) to a known active transponder on Nimiq 91W.
Notice:
To change to a Horizontal (or LH) polarity use 18V
To change to a Vertical (or RH) polarity use 13V
About polarity:
RH = Vertical = 13V (to make it easy to remember think of RV : recreational Vehicle)
LH = Horizontal = 18V