The way 'lscm' works is that for sandbox related operations such as check-in and status it will try to lock the sandbox before performing the operation. If the sandbox lock is held by some other 'lscm' daemon or RTC Eclipse client process then it will throw an error informing that the sandbox is locked.
You can run 'scm list daemon' to see the sandboxes locked by the scm processes.
So the issue could be that the first 'lscm' command run would have locked the sandbox and you running another 'lscm' command outside of the sandbox launches a separate daemon process and tries to lock the same sandbox.
You should run the second 'lscm' command either from within the sandbox or you could specify the -d/--directory option to the command and provide value as the path to the sandbox.
This issue will not occur for a remote operation such as listing a workspace or listing files of a repository workspace as it does not deal with the sandbox.