The DocuSignConnectServiceAppPool is created by the installer; you shouldn't have to create it. If it doesn't exist, but the DocuSignConnectService site exists in IIS, check the basic settings for it to see which application pool it's using. The identity of the app pool needs to be an account that has access to the Laserfiche repository it will be connecting to. Make sure the account has adequate security rights to deposit files into the specified folders. The step is described in the Using Web Access help files, and a description of the installation process can be found there too.