The following error is being reported on attempting to 
connect to the host AS400:
Unable to connect to group lu_group_1:TN5250:100.44.71.42--
rc=3  Connection Negotiation failed--LU may already be in-
use) 

Templates.log also records:
--MSGLOG-- Error: RUI Init (RUI Error 00000100:06000000 
during RUI Init, Explanation=RUI Init verb has completed 
with primary rc of Parameter Check and secondary rc of 
Reserved Field Not Zero.\n)\n

This is being experienced by an evaluator using ver 
2.0.11ga.  Previously he connected successfully (though 
that was with ver 3).  He is not aware of any change in his 
environment since then.  Connection can be made 
successfully through existing methods.

Please can you offer any suggestions? 

Templates.log and error message about to be mailed 

This looks like an incorrect definition in the LU_GROUP_1 
in the Admin Console settings.

A RUI error indicates a non-qualified host is in there, 
instead of, say *ANY.

To use the connect string indicated in the error, the group 
host definition should be *ANY.

Other way would be to make the host definition in the 
settings is *TN5250:100.44.71.42 and then just use 
LU_GROUP_1 in the connect link.