To answer your second question in your initial post, "if Acrobat is uninstalled, are LiveCycle and JBoss also uninstalled?", the answer is no, and vice-versa: if LC and Jboss are uninstalled, Acrobat is not uninstalled.
I believe we've resolved the issue. To wrap up this thread:
"org.apache.xmlbeans.XmlException: error: Invalid byte 2 of 3-byte UTF-8 sequence"
This error occurs while importing an LCA (during the preview phase) and is caused by the presence of extended characters (such as é,à,...) in a process template or the application.xml. A bug in the preview archive code prevents the import of such LCAs.
If possible, avoid using extended characters in process maps on 8.0.x systems.
However, should you run into such troubles, open the LCA file, find the application.xml and replace all extended characters with normal characters (i.e.: replace é with e). Repeat the procedure for all process templates contained within the LCA. The LCA should import now.
"Error on archive preview : C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\ArchiveStore\153\application.xml (Specified file is unreachable)"
If you follow the thread you see this error comes up after the user has rebundled the LCA after making edits to its contents. The LCA was inadvertantly rebundled as a RAR file, rather than a ZIP file.