after we installed the LLBLGEN and put the license key , we found the below error message

No license files found. please install your llblgen pro license file in the application's folder or in "my documents\LLBLGEN Pro' and restart LLBLGENPRO.exe If you downloaeded the trial version, be sure to request a trial license. Your can request one on the LLGLGEN pro website or by clicking the 'request trial license button below

please advise

and did you install the .license file in any of those folders? Please make sure its extension is .license and not .xml (it's an xml file but some email clients might change the extension to .xml)