ice.storm.print.PageDecoration not found by document [78]

 ...This has worked for years on previous versions as well as in ColdFusion 2021 since we upgraded earlier this year.  After a recent ColdFusion 2021 update the cfdocument is now throwing the error "ice.storm.print.PageDecoration not found by document" when it tries to generate the PDF file. Am I missing ome sort of Java library that handles the PDF...?

By @jeffp80876634

A suggestion inspired by the information in your question:

• Open the cfpm prompt;
• Run the command install all
  (Assuming Windows Operating System, this is equivalent to:
  - opening the command prompt CMD as administrator;
  - navigating using cd command to {CF_HOME_DIR}\cfusion\bin;
  - running the command cfpm, followed by the command install all )

Jeff, was that update 5? If so, it did have some unusual changes unlike prior ones--and the technote for it did not indicate quite all the info that has come out since, including from Adobe.

For example, and as discussed in another thread (that I see you were in fact involved in) from about a month ago, Adobe recommended clearing the felix-cache folder--to which I asked them about using the cfpm purgecache option instead (but got no reply). All that's in addition to separately clearing the cfclasses folder (both to be done while cf is down), also discussed there. Had you yet tried those?

Then there's also the longstanding possible issue that you simply had some error DURING the update. I have a post with the needed (and not obvious) details on that, which has been helping people for years to resolve "odd problems" after an update. 

Can you try those and let us know if they help or not?

The following excerpt from the stacktrace reveals the probable cause of the error:

at cfprintcandidateV22ecfm1315926517.runPage(F:\websites\GildanBangledash\hradmin\printcandidateV2.cfm:35) 
at coldfusion.runtime.CfJspPage.invoke(CfJspPage.java:257) 
at coldfusion.tagext.lang.IncludeTag.handlePageInvoke(IncludeTag.java:749) 
at coldfusion.tagext.lang.IncludeTag.doStartTag(IncludeTag.java:578) 
at coldfusion.runtime.CfJspPage._emptyTcfTag(CfJspPage.java:5201) 
at cfApplication2ecfc940188772$funcONREQUEST.runFunction(F:\websites\GildanBangledash\hradmin\Application.cfc:85) 
at coldfusion.runtime.UDFMethod.invoke(UDFMethod.java:623) 
...
at coldfusion.runtime.UDFMethod$ReturnTypeFilter.invoke(UDFMethod.java:553) 
at coldfusion.runtime.UDFMethod$ArgumentCollectionFilter.invoke(UDFMethod.java:516) 
at coldfusion.filter.FunctionAccessFilter.invoke(FunctionAccessFilter.java:95) 
at coldfusion.runtime.UDFMethod.runFilterChain(UDFMethod.java:463) 
at coldfusion.runtime.UDFMethod.runFilterChain(UDFMethod.java:438) 
at coldfusion.runtime.UDFMethod.invoke(UDFMethod.java:310) 
at coldfusion.runtime.TemplateProxy.invoke(TemplateProxy.java:975) 
at coldfusion.runtime.TemplateProxy.invoke(TemplateProxy.java:696) 
at coldfusion.runtime.TemplateProxy.invoke(TemplateProxy.java:503) 
at coldfusion.runtime.AppEventInvoker.invoke(AppEventInvoker.java:115) 
at coldfusion.runtime.AppEventInvoker.onRequest(AppEventInvoker.java:308) 
at coldfusion.filter.ApplicationFilter.invoke(ApplicationFilter.java:569) 
...

You should be using onRequestStart in Application.cfc, not onRequest.