New (to CUPS) dev ?

[null]

I'm trying to upgrade an existing (and formerly functional) custom CUPS 
environment that employed a single filter like this:

application/customtype application/postscript xx customfilter

....hacked into mime.convs (with an appropriate type filter hacked into 
mime.types)

....to a multi-staged, chain o' filters model that looks like this:

application/custom-ps-in application/custom-ps xx customsentryfilter
application/custom-pdf-in application/custom-pdf xx customsentryfilter
application/custom-pdf application/custom-ps xx pdftops
application/custom-ps application/postscript xx customprocessingfilter

....carried in proper foo.convs and foo.types files.

CUPS see the .conv, .types and filter (exes) during CUPS start but gives 
me the dreaded:

 print_job(0x401fb008[2], http://<censored>)
D [15/Nov/2004:16:02:37 -0500] print_job: auto-typing file...
D [15/Nov/2004:16:02:37 -0500] print_job: request file type is 
application/custom-ps-in.
d [15/Nov/2004:16:02:37 -0500] check_quotas(<censored>)
D [15/Nov/2004:16:02:37 -0500] check_quotas: <censored>
D [15/Nov/2004:16:02:37 -0500] print_job: requesting-user-name = 
<censored>
D [15/Nov/2004:16:02:37 -0500] Adding default job-sheets values 
"none,none"...
d [15/Nov/2004:16:02:37 -0500] copy_banner(<censored>, <censored>, none)
d [15/Nov/2004:16:02:37 -0500] add_file(<censored>, 2703, 
application/custom-ps-in)
d [15/Nov/2004:16:02:37 -0500] copy_banner(<censored>, <censored>, none)
I [15/Nov/2004:16:02:37 -0500] Job 2703 queued on '<censored>' by 
'<censored>'.
D [15/Nov/2004:16:02:37 -0500] Job 2703 hold_until = 0
D [15/Nov/2004:16:02:37 -0500] StartJob(2703,)<censored>
D [15/Nov/2004:16:02:37 -0500] StartJob() id = 2703, file = 0/1
E [15/Nov/2004:16:02:37 -0500] Unable to convert file 0 to printable 
format for job 2703!
D [15/Nov/2004:16:02:37 -0500] CancelJob: id = 2703
d [15/Nov/2004:16:02:37 -0500] add_job_state_reasons(0x401fb008[2], 2703)
d [15/Nov/2004:16:02:37 -0500] WriteClient: Removing fd 2 from 
OutputSet...
d [15/Nov/2004:16:02:37 -0500] ReadClient() 2, used=0
D [15/Nov/2004:16:02:37 -0500] CloseClient() 2
d [15/Nov/2004:16:02:37 -0500] CloseClient: Removing fd 2 from InputSet 
and OutputSet...