Just what the message says. Here is the explanation from the "Teradata Database Messsages" document.
2662 SUBSTR: string subscript out of bounds.
Explanation: This error occurs when a SUBSTR is used, and either the start position used is beyond the end of the string, the start offset plus the specified length is greater than the string length, or the specified length is negative.
Generated By: The interpretative instruction processor.
For Whom: End User.
Notes: This can be caused by an error in the second or third argument of SUBSTR.