Setup CUPS-1.4.6 in Solaris 10?

[dickson]

I compile and install CUPS-1.4.6 in /usr/local/cups-1.4.6 directory.
I use Web interface to setup a printer
I need to use the full path to send a print job as follow:
/usr/local/cups-1.4.6/etc/cups/bin/lp -d EPSON chinese_UTF8.txt

fail with the following message:
/usr/local/cups-1.4.6/bin/lp: Unsupported format 'text/plain'!

in /usr/local/cups-1.4.6/var/log/cups/error_log,
I [07/Feb/2011:14:30:56 -0800] [Job 5] Queued on "EPSON" by "webadmin".
D [07/Feb/2011:14:30:56 -0800] Returning IPP successful-ok for Create-Job (ipp:/
/localhost:631/printers/EPSON) from localhost
D [07/Feb/2011:14:30:56 -0800] cupsdSetBusyState: Dirty files
D [07/Feb/2011:14:30:56 -0800] cupsdReadClient: 11 POST /printers/EPSON HTTP/1.1
D [07/Feb/2011:14:30:56 -0800] cupsdSetBusyState: Active clients and dirty files
D [07/Feb/2011:14:30:56 -0800] cupsdAuthorize: No authentication data provided.
D [07/Feb/2011:14:30:56 -0800] cupsdReadClient: 11 1.1 Send-Document 1
D [07/Feb/2011:14:30:56 -0800] Send-Document ipp://localhost:631/printers/EPSON
D [07/Feb/2011:14:30:56 -0800] cupsdIsAuthorized: requesting-user-name="webadmin
"
D [07/Feb/2011:14:30:56 -0800] [Job 5] Auto-typing file...
D [07/Feb/2011:14:30:56 -0800] [Job 5] Request file type is text/plain.
D [07/Feb/2011:14:30:56 -0800] Send-Document client-error-document-format-not-su
pported: Unsupported format 'text/plain'!
E [07/Feb/2011:14:30:56 -0800] Returning IPP client-error-document-format-not-su
pported for Send-Document (ipp://localhost:631/printers/EPSON) from localhost
D [07/Feb/2011:14:30:56 -0800] cupsdSetBusyState: Dirty files
D [07/Feb/2011:14:30:56 -0800] cupsdReadClient: 11 POST /jobs/ HTTP/1.1


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Question : what is wrong?