T-SQL (SS2K8) :: Convert Cursor To Recursive CTE Or A Normal Query?

I have a stored proc I want to convert it to either a Normal Query using A while loop or a set based operation/recursive cte as I want to run it for multiple CompanyNames. I get the error message as An INSERT EXEC statement cannot be nested when I execute if for Multiple Companies using another Cursor

If I convert it to a Function I get the below error message

Invalid use of a side-effecting operator 'EXECUTE STRING' within a function

converting this query to a normal query or let me know if there is any change which need to done to work with multiple companynames.

CREATE PROC [dbo].[USPT] @CompanyName varchar(50),@tablename varchar(50)
AS
BEGIN
-- EXEC [USPT] 'xyz corp','Sales Header'
DECLARE @str1 VARCHAR (MAX)
set @str1 = '
DECLARE @No VARCHAR (MAX)

[code]....