nixCraft

i have ubuntu installed on my server
Linux version 2.6.15-27-server (buildd@terranova) (gcc version 4.0.3 (Ubuntu 4.0.3-1ubuntu5)) #1 SMP Fri Dec 8 18:43:54 UTC 2006

i want to act it as fax-server

i have installed External US-Robotics Fax Modem with it .
I have installed hylafax

hylafax-client 4.1.8-13ubuntu1
hylafax-server 4.1.8-13ubuntu1

after the initial configuration when i send a fax from server the fax is sent perfectly and is received on the other end as expected . But when i send fax to my server it does not receive fax as expected and in log files generates errors like these

Aug 02 05:14:02.12: [ 5984]: SESSION BEGIN 00000035 19995551212
Aug 02 05:14:02.12: [ 5984]: HylaFAX (tm) Version 4.1.8
Aug 02 05:14:07.70: [ 5984]: ANSWER: FAX CONNECTION DEVICE '/dev/ttyS0'
Aug 02 05:14: 07.70: [ 5984]: STATE CHANGE: ANSWERING -> RECEIVING
Aug 02 05:14:38.81: [ 5984]: RECV/CQ: Bad 1D pixel count, row 0, got 1904, expected 1728
Aug 02 05:14:38.97: [ 5984]: RECV/CQ: Bad 1D pixel count, row 1, got 1730, expected 1728
Aug 02 05:14:58.10: [ 5984]: RECV/CQ: Invalid 2D code word, row 3, x 292
Aug 02 05:14:58.10: [ 5984]: RECV/CQ: Bad 2D pixel count, row 3, got 292, expected 1728
Aug 02 05:15:07.59: [ 5984]: RECV/CQ: Bad 1D pixel count, row 4, got 2239, expected 1728
Aug 02 05:15:15.82: [ 5984]: RECV/CQ: Invalid EOL code word, row 5, x 0
Aug 02 05:15:15.82: [ 5984]: RECV/CQ: Bad 2D pixel count, row 5, got 0, expected 1728
Aug 02 05:15:15.90: [ 5984]: RECV/CQ: Bad 1D pixel count, row 6, got 1957, expected 1728
Aug 02 05:15:17.29: [ 5984]: RECV FAX (00000035): recvq/fax00025.tif from Fax, route to <unspecified>, 0 pages in 1:10
Aug 02 05:15:18.67: [ 5984]: RECV FAX (00000035): session with Fax terminated abnormally: COMREC invalid response received
Aug 02 05:15:18.67: [ 5984]: RECV FAX: bin/faxrcvd "recvq/fax00025.tif" "ttyS0" "00000035" "COMREC invalid response received" "" ""
Aug 02 05:15:18.71: [ 5984]: SESSION END


i have searched a lot but found no proper reason for this behaviour .
please send in your advice in this regard

thanks