PL/SQL Procedures Get Invalidated

We have an inconsistent, but frequent, problem in our non-production environment. Our web application, accessing a non-production database, will return a "page not found" error. The problem is always traced to one or more PL/SQL packages or procedures that are invalidated. Manually compiling the invalid object fixes the problem. Then, after a while, the package is invalidated again. The QA has also traced the source of the problem to clicking a back arrow on the web application (however, this does not always cause the problem, only sometimes).  

This problem exists only for databases on our TEST box, and all these databases share the same Oracle Home on this box. The PROD database, by itself on a separate box, does not have this problem (whew!). I tried to get our QA or Systems Analyst to manually run the Oracle procedure from Sql*Plus, but I am told "the package can not be run directly from sql*plus since some build in package such as OWA, which is heavily depend on http context, is meant to be called from http request/response."  

Can anybody provide me with a clue as to what is happening and what I can do to fix it? Why do we have packages that sometimes become invalidated?  

We are running Oracle 9.2.0.6 on AIX 5.1 for all databases (TEST and PROD).   Thanks!    

Sam Bootsma

Oracle Database Administrator

Information Technology Services
George Brown College

Phone: 416-415-5000 x4933
Fax: 416-415-4836
E-mail: sbootsma_at_gbrownc.on.ca <mailto:sbootsma_at_gbrownc.on.ca>  

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