On the first issue, on windows you can specify the drive as part of the dump file name:
dump tran <dbname> to 'F:/sybase/backup/tran.dmp'
On the second issue: If saptools is a mixed data and log database, it may be that all you need to do is dump tran on the saptools database. If saptools has seperated segments, then you need to enlarge the saptools database at least slightly to make more room for system data. One more MB is likely enough.