WHILE TRACKING RADIAL ACFT CDI'S BOTH SHOWED ON COURSE WHEN A 20 DEG CORRECTION WAS OBSERVED AND THE AUTOPLT FOLLOWED NAV COMMAND. AFTER TURN AND IN DSCNT ATC INTERVENED WITH IMMEDIATE CLRNC WITH VECTOR TO AVOID CONFLICTING TFC.

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WHILE ENRTE TO ASPEN; CO (KASE) ON A CLRNC DIRECT TO ASPEN ARPT APPROX 200 NM SE OF ASE ATC GAVE US AN AMENDED CLRNC WHICH READ CLRED TO KASE DIRECT TO THE RED TABLE (DBL) 145 RADIAL; 60 DME FIX; DIRECT RED TABLE DIRECT. AT THIS POINT OUR GLOBAL NAV (GPS; VLF; OMEGA) WHICH REQUIRES LAT LONG INPUTS WAS ON ASPEN (KASE) AND WE DID NOT HAVE A LAT LONG FOR THIS (DBL 145 DEG RADIAL; 60 DME) FIX; SO WE PROGRAMMED THE FIX ON OUR RNAV UNIT (A COLLINS NCS 31) AND WERE TOO FAR OUT TO GET A SIGNAL SO WE ASKED THE CTLR FOR A HDG UNTIL RECEIVING AND THE CTLR GAVE US A 15 OR 20 DEG L TURN TO JOIN THE RED TABLE 145 RADIAL TO THE FIX (DBL 145/60) WHEN RECEIVING AND THEN DIRECT DBL KASE; WITH A VERY STRONG WIND FROM THE W; WE COMPLIED WITH THE NEW CLRNC. THE CDI FROM NAV 1 AND NAV 2 INDICATED WE WERE ON COURSE. AS WE NEARED THE 60 DME FIX THE CDI GAVE A FLY L INDICATION AND THE AUTOPLT CORRECTED 20 DEGS TO KEEP IT CTRED. AROUND THIS TIME WE WERE CLRED FROM FL240 TO FL200. AT APPROX 21300 FT WITH NO INDICATION FROM ATC THAT WE WERE OFF COURSE OR ANY OTHER TFC BEING CALLED THEN OR PREVIOUSLY WE WERE TOLD IN A PANIC STRUCK VOICE TO TURN R 30 DEGS AND QUOTE 'I NEED YOU OUT OF FL210 NOW!' THE PF COMPLIED WITH THIS COMMAND. THE ACFT WAS ON AUTOPLT AT THIS TIME AND ALL TIMES PREVIOUSLY NO TFC WAS SEEN AND WERE TURNED OVER TO ASPEN APCH WITH A NORMAL APCH AND LNDG. UPON DEP FROM ASPEN; WE WERE INFORMED BY ASPEN TWR THAT ZDV NEEDED US TO CALL THEM. WHEN THE CAPT CALLED HE WAS TOLD THAT THE REVISED ROUTING HAD NOT BEEN FOLLOWED AND A LOSS OF SEPARATION HAD OCCURRED AND WE HAD COME WITHIN 4 MI HORIZ AND 700 FT VERT (CTR MINIMUM 1000 FT WITHIN 5 MI RADIUS) OF ANOTHER ACFT. THE CTR SUPVR ALSO SAID THAT THE L TURN NEAR THE DBL 145/60 DME WAYPOINT CAUSED THIS. CONTRIBUTING FACTOR: 1) THE CTLR IN THAT PARTICULAR SECTOR HAD CLIPPED THE BEGINNING OF ALL HIS XMISSIONS OFF; I BELIEVE BY TALKING TOO SOON AFTER THE XMIT SWITCH WAS DEPRESSED AND ALSO WAS CHANGING XMITTER SITES. AS A RESULT; WE WERE RECEIVING ONLY A PORTION OF OUR CALL SIGN AND SOME XMISSIONS WERE NOT COMPLETELY BREAKING THE SQUELCH. ON ALMOST EVERY XMISSION I HAD TO CONFIRM THE CALL WAS INTENDED FOR OUR ACFT. SOMETIMES I HAD TO CONFIRM MORE THAN ONCE. ADDITIONALLY THERE WAS AN ACFT WITH A SIMILAR CALL SIGN ON THE SAME FREQ. 2) I BELIEVE THE CTLR AT THAT TIME HAD A HIGH WORK LOAD AND HAD FORGOTTEN HE HAD GIVEN US A L TURN TO JOIN THE DBL 145 DEG RADIAL PRIOR TO THE FIX AND FLY IT UP TO FIX WHEN WE WEREN'T RECEIVING. 3) WE DID A VOT CHK THAT MORNING AND BOTH VORS INDICATED A 0 DEG ERROR. ON THE RETURN LEG TO HOU I WAS THE PF. WHILE TRACKING DIRECT TO MERIT INTXN NAVASOTA (TNV 125 DEG RADIAL 7 DME) HOUSTON CTR POINTED OUT THAT THEY SHOWED US OFF COURSE; AT THAT TIME I LOOKED AT MY CDI AND IT WAS CTRED. CONCLUSION: I BELIEVE THE PRIMARY CAUSE OF THIS INCIDENT LIES WITH THE ZDV PROC CONCERNING ACFT SPACING ON OPPOSITE DIRECTION OR XING TFC; AND CONCERNING THE PARTICULAR CTLR RAPID FIRE CLRNCS COMBINED WITH POOR RADIO TECHNIQUE ONLY SERVES TO ADD TO FREQ CONGESTION WHEN A CLRNC REQUIRES 2 OR 3 XMISSIONS TO ATTEMPT TO VERIFY.