I know the OP probably doesn't need an answer any more, but for anyone who has a similar issue and ends up finding this question:
The message text 'An insufficient number of arguments were supplied for the procedure or function cdc.fn_cdc_get_net_changes_' is very misleading or you could even call it incorrect. It means the value you've specified for @from_lsn and/or @to_lsn is invalid or out-of-bounds. Usually the value specified for @from_lsn is before what is still available for this particular source table (the cleanup process has deleted the rows you intended to read).
The smallest lsn available for a capture instance can be found by calling:
declare @min_lsn binary(10);
select @min_lsn = sys.fn_cdc_get_min_lsn('dbo_yourtable');
where 'dbo_yourtable' should be replaced by the name of your capture instance of course.
The highest lsn for any capture instance can be found from:
declare @max_lsn binary(10);
select @mx_lsn = sys.fn_cdc_get_max_lsn();
As you can see, the min_lsn may be different per capture instance, whereas the max_lsn is the same for all capture instances.