Failing to connect issues when doing remote install

I have to reinstall agents remotely while user is connected to checkpoint VPN. When I check the log i see this error (the machine doesn't show up in the console)

<event date='Jun 25 11:09:47' severity='2' hostName=HOST' source='AeXNetworkTransport' module='AeXNetComms.dll' process='AeXNSAgent.exe' pid='2996' thread='3800' tickCount='10584546' >
  <![CDATA[Post to 'HTTP://server.domain.com/Altiris/NS/Agent/CreateResource.aspx' failed: Invalid data received in HTTP response. Expected 2857 bytes, received 0 (-2147024883)]]>
</event>
 

<event date='Jun 25 11:09:47' severity='2' hostName='HOST' source='CoNetworkTransport(258)' module='AeXNetComms.dll' process='AeXNSAgent.exe' pid='2996' thread='3800' tickCount='10584546' >
  <![CDATA[Invalid data received in HTTP response. Expected 2857 bytes, received 0 (-2147024883)]]>
</event>

Do ports need opened up ?

I can ping OK, I can copy the agent install file to the local drive and initiate install using psexec.

Any IDEAS ?