SQL & PL/SQL :: Export To A File

I am having an issue export to a file. When I ran the code below I got the correct result. However I want to have a stored procedure to accept schema and table as parameters and pass it so that the records in the table in that schema is exported to a csv file.

CREATE OR REPLACE Procedure sp_export
IS
BEGIN
DECLARE
vfilename varchar2(30);
vFile utl_file.file_type;
CURSOR myCur IS SELECT * FROM user11.system_log_by_range;
[code]...

I tried this procedure with parameters and got an error about EXECUTE IMMEDIATE at the cursor.

CREATE OR REPLACE Procedure sp_export (s in varchar2, t in varchar2)
IS
BEGIN
DECLARE
vfilename varchar2(30);
vFile utl_file.file_type;
CURSOR myCur IS EXECUTE IMMEDIATE 'SELECT * FROM '||s||'.'||t;
[code]....