BIP timing out

Hello,

we are using BI Publisher as a tool for documents/reports generation from Siebel. Most of the Documents (70%) get generated fairly quickly (<5s), while 30% takes more than 40 seconds to generate. There is nothing inbetween. I checked both Siebel and BIP log and it looks like there is a problem in BIP. All the time when report takes more than 40sec to generate, there is a connection time out. See attached part of log.

Do you have any advise where to look and where does the connection time out comes from? Is it connection to EAI component on Siebel? Why does BIP does not keep the connection?