Hi Arthur,

The program doesn't allow the separate closing of the Sales and Purchase modules. You can check out the Stock Status on the Fiscal periods under Common data, G/L Accounting Tables to see if this helps at all. This is what the Online help says about the field:

This field makes it possible to indicate the period status for the stock:

• Direct 
  The period is open to all movements.
• Balance adjustment 
  The period is open to price adjustment movements only. If not absorbed movements exist, they are posted on the first open fiscal period available. This status is used to modify an existing stock transaction (shipments, receipts, etc.) and to launch the price adjustment processing (issues and receipts).
• Prohibited 
  The period is prohibited for any movement (for the end of month processing).The average cost and other value totals are not recalculated, variances are considered as being not absorbed and are posted on the first open fiscal period available.