Error when executing procedure "[Information] Syntax check (x:x): Found: 'SAMPLE' The name of th (4307691)

I am having a problem debugging an Oracle procedure using Toad version 10.6.1.3. Here are the steps I'm running:

1. Right click on procedure from Schema Browser view and select load in editor
2. Toggle debugging option on
3. Select 'set execution parameters'

Toad GUI does not bring up the form to enter the parameters. It presents the following informational error:
"[Information] Syntax check (x:x): Found: 'SAMPLE' The name of the identifier might conflict with a keyword"

Here is some code which demonstrates the issue.

CREATE OR REPLACE PROCEDURE LIMSLV.SP_DEBUG_PROCEDURE
(
IN_SAMPLEID IN NUMBER
,proc_error_code OUT VARCHAR2
)
AS

V_SAMPLEID NUMBER;

BEGIN

BEGIN
SELECT 10
INTO V_SAMPLEID
FROM DUAL SAMPLE;
EXCEPTION
WHEN OTHERS THEN NULL;
END;

END;

/