Zen Cart 1.3.8a, hosted by Ipower: linux PHP 5.2.17

Gateway is First Data / Linkpoint.

Store has been working great for 6 months. No changes or updates made, except adding some products to the store in early January.

Last good transaction was 1/22/11; since 2/4/11 we get the same payment error on every transaction.

Customer sees credit card declined. Linkpoint CC review shows SGS - 020006.

First Data gave us a new pem and checked it. They say it is working.

Here is linkpoint debug file from our public_html/cache:

Feb-08-2011 02:22:03
=================================

Response Code:

Sending to Gateway:
result = LIVE
oid = 1356-WUqTxd
ip = 173.64.222.30
ponumber =
subtotal = 1
tax = 0.08
shipping = 0.00
chargetotal = 1.08
cardnumber = ******
cardexpmonth = 04
cardexpyear = 11
cvmindicator = provided
cvmvalue = ******
userid = 1
customerid = 1
name = My Name
company =
address1 = 4111 Your St.
address2 =
city = Your City
state = Texas
country = US
phone = 972-111-2222
email = [email protected]
addrnum = 4111 Your St.
zip = 75000
sname = My Name
saddress1 = 4111 Your St.
saddress2 =
scity = Your City
sstate = Texas
szip = 75000
scountry = US
comments = Website Order
items = Array
(
[1] => Array
(
[id] => 52:9abf9dc1d41ae94abcb780afcac8ebdc
[description] => Buttery
[quantity] => 1
[price] => 1.00
[options0] => Array
(
[name] => Size
[value] => Mini
)

)

)

ordertype = SALE
host = secure.linkpt.net
port = 1129
keyfile = /our/root/path/name/public_html/includes/modules/payment/linkpoint_api/xxxxxxxxx.pem
configfile = xxxxxxxxx
transactionorigin = ECI
terminaltype = UNSPECIFIED


Result:
(
[r_csp] =>
[r_time] =>
[r_ref] =>
[r_error] => SGS-020006: Please contact merchant services.
[r_ordernum] =>
[r_message] =>
[r_code] =>
[r_tdate] =>
[r_score] =>
[r_authresponse] =>
[r_approved] =>
[r_avs] =>
)

##############################

After reading a related thread here by Dr. Byte, we have run this:
http://ourwebsite.com/extras/curltest.php?linkpoint=1, and have this output:

Array
(
[url] => "https://secure.linkpt.net:1129/LSGSXML"
[content_type] =>
[http_code] => 200
[header_size] => 40
[request_size] => 175
[filetime] => -1
[ssl_verify_result] => 0
[redirect_count] => 0
[total_time] => 0.786676
[namelookup_time] => 0.050543
[connect_time] => 0.152435
[pretransfer_time] => 0.678138
[size_upload] => 37
[size_download] => 280
[speed_download] => 355
[speed_upload] => 47
[download_content_length] => 280
[upload_content_length] => 0
[starttransfer_time] => 0.786609
[redirect_time] => 0
)

Malformed or unrecognized request. EOF

##############################___

We believe this shifts issue toward the hosting provider, so we have asked them about port 1129 and CURL issues.

Can the experts here please advise other tests we can do, or other questions we can ask of gateway or hosting provider to help pinpoint the cause of this error?