In order to run your Oracle Forms application utilizing the WebUtil functionality, the Forms and Reports environment must be properly set up:

1. You must use the webutil.olb and webutil.pll that came with the Forms install. You should NOT copy any versions from other platforms. For example, if you are deploying your application in Linux after developing some forms in Windows, you should not copy any WebUtil library from Windows to Linux (or vice-versa). Basically, make sure the webutil.pll you compiled is one that came with the Forms installation. Otherwise, you may encounter strange issues such as FRM-40735/ORA-06502 or ORA-06508.

2. Make sure that the WebUtil libraries (olb, pll, and plx) are not in more than one location in the FORMS_PATH.

3. Inside formsweb.cfg in each application section(s), it/they will need to at least have:

baseHTMLjpi=webutiljpi.htm
baseHTML=webutilbase.htm
WebUtilArchive=frmwebutil.jar, jacob.jar
WebUtilLogging=off
WebUtilLoggingDetail=normal
WebUtilErrorMode=Alert
WebUtilDispatchMonitorInterval=5
WebUtilTrustInternal=true
WebUtilMaxTransferSize=16384

4. In $ORACLE_HOME/forms/webutil/win32, the file jacob-1.14.3-x86.dll needs to be present

5. In $ORACLE_HOME/forms/webutil/win64, the file jacob-1.14.3-x64.dll needs to be present

6. In $ORACLE_HOME/forms/java, jacob.jar must be present there. If you are using Java Runtime Environment (JRE) 7u51 or higher, it will need to be signed with trusted code-signing certificates or your application may get blocked when running in the web browser.

7. Make sure that a public synonym WEBUTIL_DB has been created in your Oracle Database and is granted on execute to public (GRANT EXECUTE ON WEBUTIL_DB TO PUBLIC;)

8. Make sure in $ORACLE_INSTANCE/config/FormsComponent/forms/server/webutil.cfg that the following parameters are set to what they are below (these parameters are found close to the very bottom of the file):

transfer.database.enabled=TRUE
transfer.appsrv.enabled=TRUE
transfer.appsrv.workAreaRoot=
transfer.appsrv.accessControl=FALSE

That should be everything that is required in the environment for WebUtil to work in Forms.

Source: Oracle Support note 1093985.1 (How to Configure Webutil in Forms 11g)