Synopsis
This is an error in the way the REXX script is written. There is an IF or WHEN keyword without a subsequent, matching THEN keyword.
Cause
You put an IF or WHEN keyword without a corresponding THEN keyword after it.
Cure
IF or WHEN can't be used without a subsequent THEN. Make sure that there is one THEN keyword after every IF or WHEN keyword.
Cause
You tried to name a variable if or when in a place where the IF or WHEN keywords are illegal.
Cure
In certain instructions, you cannot use the (unquoted) REXX keywords IF or WHEN for a variable name.