DFS3818 INTERVAL KEYWORD PARAMETER IS MISSING OR INVALID

Explanation
 A /CHANGE SURVEILLANCE command
was rejected for one of the following reasons:   
The INTERVAL value was missing or invalid.

More than one INTERVAL value was entered.

The INTERVAL value must be greater than
0 and less than 100.

System action
 The command is rejected.

Programmer response
 Correct the INTERVAL value; then reenter
the command.