Problem Symptoms:
When customer try to connect to the GUI in the first time he gets the following error messages 
communication error (global -5) 

failed to connect to host

Cause:
In AL500/ALEPHCOM/TAB
in file Library.ini in the parameter PCVER contain wrong address or port

Resolution:
in AL500/ALEPHCOM/TAB
in file Library.ini in the parameter PCVER the parameter PCVER should contain the correct address server from which we want to download update for the GUI