If that happens your database crashed in the middle of a transaction and then (on purpose) it will not start until you decided what you want to do with the transaction that was going on during the crash.
You can use the log translation function to translate the log to what was going on and the force the system to ignore that last transaction by starting once with the -f option:
Sybase refused to recover with the log file present. Basically the error message was the same as before.
After removing the log files recovery went as expected.
Makes me think again if I should implement backup scripts again
Although nothing critical is in these databases I would not have liked to spend (too much) time to rebuild them.