Can you provide any specifics about how the transaction differs from being played back using the recorder vs when it's assigned to a player? Occasionally there are browser differences that might cause issues. I would recommend if you're having trouble to create the recording on the same server where the player is installed. Also, ensure you're logged into the machine where you're creating the recording as a local user account since the player runs these transactions using local user accounts. These two steps should help ensure you are mimicking the player behavior with the SeUM Recorder as much as possible. On a related note we should be releasing a service release for SeUM 1.5 later this week to address a few customer reported issues. I can't say your issue is addressed in this service release but I would recommend upgrading once it's available and to see if it helps.