check the dates properly
in finance integration tables, first check what are the Transaction Date & Log Date carefully for each of the unposted transactions. try posting them accordingly.
if still the posting does not happen. then for each of the PCS project, check Form 2 in Maintain Projects session. check fields like 'Post Cost Price and Turnover sales if not closed' , 'Posting Date Cst/Turnover Sls', etc. You might need to change the date value in 'Posting Date Cst/Turnover Sls'.