You need to connect with a LiveCycle server. See here. http://helpx.adobe.com/livecycle/help/mobile-forms/preview-xdp-forms-html.html

Also verify in Acrobat (Edit > Preferences > Internet) it's using Acrobat/Reader to view PDF documents.

Have you tried reinstalling LiveCycle Designer? It should then pick up that Acrobat Pro XI is present and use it for Preview.

7.x version also reached end of life on 6/30/2013. http://www.adobe.com/support/products/enterprise/eol/eol_matrix.htmlCheck if you had a Maintenance & Support contract and if so, you would have a more recent version available as part of the support contract.

They may be encountering a probelm where the Google Chrome, Safari, or Firefox PDF viewer is used instead of Adobe Reader. See here for how they can set the browser to use Adobe Reader. http://helpx.adobe.com/livecycle/kb/xfa-forms-firefox-chrome.html

After reviewing the sample PDF's, it was determined that 1 form was saved as Static PDF and the other Dynamic PDF. The Please Wait... message was displayed by the Dynamic PDF becuase it was openned in another PDF Viewer other than Adobe Reader. Links to reference: http://helpx.adobe.com/livecycle/kb/xfa-forms-firefox-chrome.html and http://help.adobe.com/en_US/livecycle/10.0/DesignerHelp/WS92d06802c76abadb-728f46ac129b395660c-7ef1.html for chosing Static vs Dynamic.

Can you share that PDF?

Did he receive the "Please Wait.." message as you noted above with the one PDF that doesn't open?

Forms created with LiveCycle Designer are XFA-based forms.

Check the PDF Viewer used in the browser. See here: http://helpx.adobe.com/livecycle/kb/xfa-forms-firefox-chrome.html

Have a look at this blog with the same error and suggested solutions. http://blogs.adobe.com/dmcmahon/2012/09/16/livecycle-designer-es2-word-version-xp-or-onwards-could-not-be-found-on-the-machine/

You may also find this information regarding Best Practices for XFA form design helpful. http://www.adobe.com/devnet/livecycle/articles/best-practices-xfa-forms.html

If you are looking to evaluate LiveCycle Designer, you should evaluate the latest release. Trial download available here: www.adobe.com/go/trylivecycle_designer

See this similar post.  http://forums.adobe.com/message/5611303#5611303

Adobe LiveCycle ES4 has included functionality for Mobile Forms processing leveraging already created form templates from LiveCycle Designer. See this link for more details. http://helpx.adobe.com/livecycle/help/mobile-forms/introduction.html

Do you also have a LiveCycle Server installed? The local path you provided above is for the client side LiveCycle Designer tool. You need to connect with a LiveCycle Server (separate installation from LiveCycle Designer ES4) to generate the HTML preview. Documentation for HTML Preview configuration: http://helpx.adobe.com/livecycle/help/mobile-forms/preview-xdp-forms-html.htmlDocumentation for LiveCycle Server Installation: http://helpx.adobe.com/livecycle/topics/installing-upgrading-clustering....

It appears as if the Firefox and Chrome PDF Viewer is active vs the Adobe Reader. The type of PDF created requires Adobe Reader to view. Please see here for activating the correct PDF viewer. http://helpx.adobe.com/livecycle/kb/xfa-forms-firefox-chrome.html

Firefox and Chrome also have built-in PDF Viewers. You need to use Adobe Reader/Acrobat for PDF's created from XFA forms. It's likely the browers built-in PDF Viewer is attempting to load the PDF which explains why you are receiving the "Please wait..." message.

To receive this patch you will need to contact Adobe Enterprise Support. Please reference defect id#2695467 and they will evaluate further confirming you have the same problem and deliver you the fix.