Hi Marco,
I see this failure when the soft ioc failed to start. There are other system-related reasons.
Currently, the LCLS group at SLAC is changing to no longer start soft IOCs using the SLAC version of iocConsole and instead will use something called procServ - Ernest can give details. Apparently, the soft IOC can freeze while somebody is paging up and down inside of screen - I've not reproduced it and debugged it though. I also see that Ralph Lange uses something called conServer which looks interesting:
http://epics.aps.anl.gov/epics/wiki/index.php/How_to_Set_Up_Console_Access_and_Logging_for_VME_and_Soft_IOCs
Sorry I cannot be more help,
Stephanie Allison