WW24 PIC DSNDS FROM LAS TYSSN STAR; DISTR BY GPS EQUIP PROBS; HOLDING INSTRUCTION; OVERWHELMED FO AND ASSUMED INTENT OF L30 STAR CLRNC.

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AT APPROX XA00 I WAS FLYING AS CAPT TO LAS. THIS WAS A DAY TRIP FOR ME; NOT MY REGULAR JOB OR ACFT THAT I FLY (ALSO A WESTWIND) ON A ROUTINE BASIS. ABOUT 100 MI FROM LAS; I HEARD RADIO TFC STATING TO EXPECT HOLDING INTO LAS DUE TO VIP MOVEMENT. WE WERE RECLRED FROM PEACH SPRINGS 1 TO THE TYSSN 1 RNAV ARR; AND TOLD TO DSND AND MAINTAIN 13000 FT. SUBSEQUENT TO THAT CLRNC; WE WERE GIVEN CLRNC TO 'HOLD AT KADDY AS PUBLISHED' AND GIVEN AN EFC TIME. I ASKED FOR AND RECEIVED PERMISSION FOR 10 MI LEGS IN THE HOLD. DURING OUR SECOND TURN IN THE HOLDING PATTERN; AND APPROX 10 MI FROM KADDY INTXN; WE WERE CLRED DIRECT TO KADDY TO RESUME THE ARR AND INSTRUCTED TO COMPLY WITH THE ALTS DEPICTED ON THE ARR. AT THAT TIME; WE BEGAN HAVING PROBS WITH THE TRIMBLE GPS (THE WESTWIND THAT I NORMALLY FLY HAS A GNSXLS). THE TRIMBLE UNIT WAS SLOW IN ITS CALCULATIONS AND DID NOT RECOGNIZE SOME OF THE WAYPOINTS ON THE ARR. AT THE SAME TIME; I HEARD WHAT I BELIEVED THE CTLR TO SAY; 'DSND AND MAINTAIN 10000 FT;' AND THIS WAS READ BACK TO HIM. 10000 FT WAS SET IN THE ALT SELECT. 10000 FT IS ALSO THE NEXT MANDATORY ALT FOR XING THE NEXT WAYPOINT ON THE ARR; AND IT WOULD MAKE SENSE THAT PERHAPS HE WANTED US THERE NOW. IN MY MIND; THIS NEGATED THE CLRNC TO COMPLY WITH THE DEPICTED ARR ALTS; WHICH INCLUDED XING KADDY AT 12000 FT. WE CONTINUED OUR DSCNT TOWARDS 10000 FT AND JUST PRIOR TO REACHING KADDY AND AT AN ALT OF 11000 FT; THE CTLR CAME ON AND TOLD US THAT OUR CLRNC WAS TO COMPLY WITH THE ALTS DEPICTED ON THE ARR; AND WHY WEREN'T WE AT 11000 FT? I REPLIED THAT I HAD UNDERSTOOD THE CLRNC TO BE DSND AND MAINTAIN 10000 FT. HE TOLD US TO MAINTAIN 11000 FT. HE THEN INFORMED US THAT WE HAD MISSED KADDY BY 3 MI; SO I KEYED THE MIKE AND APOLOGIZED FOR THE CONFUSION AND THAT WE SEEMED TO BE HAVING SOME PROBS WITH THE GPS ACCEPTING DATA. AT THAT POINT; HE GAVE US A HDG OF 360 DEGS TO REJOIN THE ARR. FROM THAT POINT; THE REMAINDER OF THE ARR AND APCH WERE NORMAL. THERE DID NOT SEEM TO BE ANY CONFLICTS THAT AROSE OUT OF THIS SIT; AND HE SEEMED SATISFIED WITH MY EXPLANATION. EXTENUATING CIRCUMSTANCES INCLUDED A RELATIVELY NEW COPLT WHO WAS A BIT OVERWHELMED BY THE SPD AT WHICH CHANGES WERE OCCURRING; AND AS A RESULT; ME HAVING TO DO THE FLYING; NAVING; AND COMMUNICATING. AFTER WE LANDED; MY COPLT; WHO IS EMPLOYED BY THE COMPANY THAT I WAS DAY PLTING FOR; INFORMED ME THAT THE TRIMBLE GPS DID NOT HAVE SOME OF THE WAYPOINTS ON THE RNAV ARR IN ITS DATABASE. OBVIOUSLY; THE MISSED ALT WAS AN ERROR ON MY PART; AND IS THE FIRST OCCURRENCE OF ITS KIND IN THE 15 YRS I HAVE BEEN FLYING A CPR JET. I SHOULD HAVE VERIFIED ALTS WITH THE APCH CTLR; EVEN THOUGH I THOUGHT I WAS CLR IN OUR DSCNT INSTRUCTIONS. IN RETROSPECT; I SHOULD HAVE INFORMED THE APCH CTLR OF THE PROB WITH THE GPS ACCEPTING RNAV WAYPOINTS AND ASKED FOR A RADAR VECTOR. THIS DISTR; ALONG WITH THE OTHERS MENTIONED; WAS A MAIN CONTRIBUTING FACTOR IN OVERLOOKING THE MANDATORY XING OF KADDY AT 12000 FT; AND CONTINUING THE DSCNT TOWARDS 10000 FT; WHICH IS WHAT I BELIEVE I HEARD AND READ BACK; EVEN THOUGH WE HAD REVIEWED THE ARR AND DISCUSSED THESE ALTS. UPON RETURNING TO MY HOME BASE; I DISCUSSED THE EVENTS WITH MY CHIEF PLT AND HE URGED ME TO RPT THIS EVENT TO YOU. I PRIDE MYSELF ON DEMONSTRATING THE UTMOST IN PROFESSIONALISM; AND AM AMAZED HOW QUICKLY A ROUTINE FLT BECAME A BIT CHAOTIC. AS THEY SAY; IT'S NEVER ANY ONE THING THAT GETS YOU IN TROUBLE; BUT RATHER A CHAIN OF EVENTS; AND THIS WAS CERTAINLY THE CASE ON THIS DAY.