invalid object name 'sys.objects'

Our scripts have a sql server 2005 requirement.Some of our customers have reported the error invalid object name 'sys.objects' . On going through some of the posts in this forum it seems to me that sys.objects is a view introduced in sql server 2005. So i suspect this problem might be occuring because the user is trying to run our script on an older version of sql server. I want to know if this is the only possibility or if there is any other case this error can occur in sql server 2005.

Thanks,
CCThat is the obvious possibility. It seems very unlikely that a system catalog view was dropped or tampered with.