We faced this error after migrating to shared application file system on one of our dev instances. Forms sessions would not start up through self service or through dev60cgi/f60cgi and report these errors:
Oracle Forms Web CGI: Error detected
Your request cannot be serviced at this time due to the following error:
ERROR: Parameter "userid" not found in URL or configuration parameters.
After a lot of tests I came across Metalink Note: 299206.1 which pointed the cause as:
This error indicates that the baseHTML (typically this is =%OA_HTML%/US/appsbase.htm) file for forms has parameters which are not defined in the associated appsweb*.cfg file.
In other words the appsbase.htm and appsweb.cfg are out of sync.
However we followed the steps given to compare and found that appsbase.htm and appsweb.cfg were in sync. We then checked the versions of appsbase.htm on a different instance and found that the version of appsbase.htm in web tier and concurrently tier were very different.
$ adident Header appsbase.htm
$Header appsbase.htm 115.40 2008/03/05 06:12:28 upinjark ship $
$ adident Header appsbase.htm.original
$Header appsbase.htm 115.9 2001/06/11 19:59:45 pkm ship $
During migration to shared appl_top we had mistakenly preserved the older appsbase.htm of concurrent tier and did not copy the newer appsbase.htm of web tier.
After copying the latest appsbase.htm from a different instance, the problem was resolved.