IIS server restart required to convert web pages to PDF using COM-Collection of common programming errors

Have an annoying issue with our production web servers. Windows 2008 R2 x64, fully patched, using php 5. Also installed is ABC PDF, php will call the COM object to convert a web page to PDF and present to user.

After 2-8 weeks or normal operation, php can no longer convert pages to PDF, and throws error like this Uncaught exception ‘com_exception’ with message ‘Source: ABCpdf
Description:Unable to render HTML. Unable to create MSHTML document. COM error 80070008. Not enough storage is available to process this command

Here are fixes I have tried without success: 1. IISRESET 2. reinstall and re-register ABC PDF 3. Shut off all other non essential services on the server 4. Verified we have sufficient disk space on all drives and RAM 5. Modified ABC PDF to use the Mozilla browser engine that is installed with it instead of relying on IE9 installed on the web server 6. upgrade one server from 8GB to 32GB RAM, this had no impact on the behavior or the amount of time it will run succesfully

I have three identical web servers in a MS NLB cluster. They will all start to exhibit this behavior within 24 hours of one another. Only a full server restart will clear this issue and allow PDF creation to continue.

Suggestions or similar experiences?

Originally posted 2013-11-27 05:08:07.