Hi BW system is connected check for the issues in logical systems and try to reactivate it.if you are in DEV enviroment,Please log in to customizing client and go to lbwe,activate the structures by adding a new filed from comm str to ext str and click on ok then capture this in customize TR and then come to lbwe remove the newly added field and capture the changes in the earlier TR and log out.Login to dev client go to scc1 tcode now mention the customizing client as source and dev client as target and give the TR name and execute.now check.It should work.
Regards,
Rambabu