If you require the number of rows at the output from the proc then try this:

create Procedure dbo.RecCount (@Table as nvarchar(100)) As

Begin

    DECLARE @cntTotal varchar(10)

    DECLARE @sql nvarchar(400)

    set @sql = N'select @cnt=count(*) from ' + @Table

    exec sp_executesql @sql, N' @cnt varchar(10) output', @cnt=@cntTotal output

    select @cntTotal

End