REBOL 3 Errors: header

An attempt was made to evaluate a file as a REBOL script and the file did not have a REBOL header.

Message:

Script is missing a REBOL header

Example:

write %no-header.r {print "data"}
filter-error try [do %no-header.r]
** Syntax Error: Script is missing a REBOL header
** Where: do %no-header.r