ACR FLC TOOK A CLB CLRNC FOR ANOTHER ACFT.

Narrative

CLBING THROUGH ABOUT 15000 FT MSL; THE FO DISCOVERED A PROB WITH THE AUTOPLT TURNING TO THE L. WHILE TROUBLE- SHOOTING THE PROB; WE LEVELED AT FL190 AND THE FO HAND FLEW THE AIRPLANE. WE ALSO DISCOVERED THE ALT ALERTER WAS NOT WORKING PROPERLY. CAPT ASKED THE FE TO CHK THE AURAL WARNING CIRCUIT BREAKER. THE FE FOUND NO CIRCUIT BREAKERS POPPED. MEANWHILE; WE RECEIVED AN ATC HDOF TO THE NEXT SECTOR. THE CAPT MADE THE CHK IN AT FL190 WITH CTR WHICH WAS VERY BUSY. THE CTLR ACKNOWLEDGED THE CHKIN AND GAVE A CLB CLRNC TO FL330. THE CAPT ACKNOWLEDGED THE CLRNC TO FL330 AND WE BEGAN TO CLB. LATER; THE FO SAID WE WERE FLT PLANNED TO ONLY FL250. THE CAPT THEN INQUIRED WITH ATC ABOUT OUR ASSIGNED ALT. THE CTLR STATED THAT WE HAD TAKEN A CLRNC TO FL330 THAT WAS INTENDED FOR ANOTHER ACFT. WE WERE THEN INSTRUCTED TO STOP OUR CLB AND LEVEL AT FL220. THERE WAS NO INCIDENT WITH OTHER ACFT. A COMBINATION OF FACTORS INCLUDING MALFUNCTION OF COCKPIT EQUIP; CONGESTION OF THE ATC FREQ CONTRIBUTED TO THIS OCCURRENCE.