Trouble with multilink interface with PPP

[ontrack]

I have setup a PPP multilink interface that is supported by 2 T1 PPP links. The situation is that everything seems to be working, I can ping in and out I can web browse and ftp from the ethernet interface to the internet. The problem comes in when I attempt to access services on the ethernet interface from the internet. For instance I have a web site, a Citrix portal and a FTP site that I can not establish a connection with from the outside. The weird thing about it is that the client can get to the server but the server can not establish a connection back to the client. To help illistrate this I can establish a passive FTP to the FTP server but not a standard FTP connection. Any ideas would be much appreciated. Thanks.

[ontrack]

To help I thought that I should include the multilink conf portion of my setup.

interface Multilink1

ip address X.X.X.X 255.255.255.252

no cdp enable

ppp multilink

ppp multilink fragment-delay 1000

multilink-group 1

interface SerialX/1:0

no ip address

encapsulation ppp

no fair-queue

ppp multilink

multilink-group 1

interface SerialX/2:0

no ip address

encapsulation ppp

no fair-queue

ppp multilink

multilink-group 1

ip route 0.0.0.0 0.0.0.0 multilink1