What version is your Application Server? According to the website: [url http://www.oracle.com/technetwork/developer-tools/forms/webutil-090641.html]Oracle Forms WebUtil "Oracle WebUtil is delivered and installed as a component of the Oracle Developer Suite 10.1.2 and of Oracle Fusion Middleware 11g". If you are using an older version, then you would have to download it and install it yourself. You can find it at [url http://www.oracle.com/technetwork/developer-tools/forms/readme-082817.html]WebUtil Version 1.0.6 - and follow the instructions.
By default you will not find a webutil folder in ORACLE_HOME\forms directory, you have to create it.
If you have access to MOS i recommend you to look for note 566628.1 "How To Install Webutil on 10.1.2.x Oracle Application Server" in order to install webutil correctly :)
I recommend you to upgrade your oas from version 10.1.2.0.2 to 10.1.2.3 since that problem may be the result of a bug and may be fixed with this upgrade, and after that you should also apply bundle patch 9593176 so in resume: