-Disband fleet (if income still negative...)
-Sell your stuff on the market (if income still negative...)
-Get some friends to use positive dineros on you (if income still negative...)
-Beg your slavemaster to tribute you. (If slavemaster refuses or you do not already have one - do note, asking somebody to enslave you is against game rules ...)
-You are teh pwnd. Reset, `cuz you are unable to get outta debt.