the following sp causes the same error.
"..is not a valid floating point value" in debug mode.

CREATE PROCEDURE P_TESTCONCAT
AS
DECLARE VARIABLE TXT VARCHAR(2000) DEFAULT '';
DECLARE VARIABLE CTX VARCHAR(13) DEFAULT ' BEZEICHNER: ';
DECLARE VARIABLE NUM INTEGER DEFAULT 12345678; /* THIS IS A VALID
NUMBER, INTEGERS CAN STORE UP TO 2,147,483,647 */
DECLARE VARIABLE LEN INTEGER;

BEGIN
TXT = TXT || CTX || CAST(NUM AS VARCHAR(8)); LEN = STRLEN(TXT);
TXT = TXT || CTX || CAST(NUM AS VARCHAR(8)); LEN = STRLEN(TXT);
TXT = TXT || CTX || CAST(NUM AS VARCHAR(8)); LEN = STRLEN(TXT);
TXT = TXT || CTX || CAST(NUM AS VARCHAR(8)); LEN = STRLEN(TXT);
TXT = TXT || CTX || CAST(NUM AS VARCHAR(8)); LEN = STRLEN(TXT);
TXT = TXT || CTX || CAST(NUM AS VARCHAR(8)); LEN = STRLEN(TXT);
TXT = TXT || CTX || CAST(NUM AS VARCHAR(8)); LEN = STRLEN(TXT);
TXT = TXT || CTX || CAST(NUM AS VARCHAR(8)); LEN = STRLEN(TXT);
TXT = TXT || CTX || CAST(NUM AS VARCHAR(8)); LEN = STRLEN(TXT);
TXT = TXT || CTX || CAST(NUM AS VARCHAR(8)); LEN = STRLEN(TXT);
TXT = TXT || CTX || CAST(NUM AS VARCHAR(8)); LEN = STRLEN(TXT);
TXT = TXT || CTX || CAST(NUM AS VARCHAR(8)); LEN = STRLEN(TXT);
/* THE NEXT COMMAND CAUSES THE ERROR, THE LENGTH OF THE RESULT
EXCEEDS 255 CHARACTERS */
TXT = TXT || CTX || CAST(NUM AS VARCHAR(8)); LEN = STRLEN(TXT);
END

regards, christoph