Intermittent problems while launching IM from portal channel

We have installed the whole JES suite of products. We are now playing with instant messaging. When going throught the gateway, we sometimes get an error when launching IM (Java Webstart mode) from the IMChannel:

"The following required field is missing from the launch file: <jnlp>.

I then click the same link and it launches fine.

Any help would be appreciated,

Steve

[412 byte] By [wiggam] at [2007-11-25 10:53:20]
# 1
The portal im channel dynamically generates the jnlp file based on session and profile information . This error usually happens when jnlpLaunch.jsp in the IM provider encounters an exception.More information can usually be gathered from the web container logs.
belissent at 2007-7-1 21:53:18 > top of Java-index,E-Mail, Calendar, & Collaboration,Sun Java System Instant Messaging...