The error condition received looks to be acceptable and within the 63 characters mentions in the utility guide. (messages is 61 character)
The 63 characters noted refer to the entire statement. Not just the message text
Release : 7.7
Component : CA-PDSMAN for OS/390
Provided example on using the correct statement syntax. Recommend using the CONT statement on longer scan strings.
SCAN TARGET='SMP/E PROCESSING IS COMPLETE. ',
CONT='THE HIGHEST RETURN CODE WAS 00.'
This example resolved this particular issue but bear in mind the length of the message being scanned.