Element SYS is undefined in CLIENT

[ajp-bio-8012-exec-9] - Element SYS is undefined in CLIENT. The specific sequence of files included or processed is:

We are getting the above error quite frequently when moved from ColdFusion 4.5 to ColdFusion 10 recently. I tried to use the default client variable storage to registry. Someone help me out on this error related to storing client varaibles? I'm seeing this issue recently after upgrading to CF10.