i'm running the latest dev version - 7.x-1.0-beta3+7-dev - and the 7.x-2.0-alpha7 version of Feeds, 7.x-1.2 of ctools. started getting this error about "Missing Feeds plugin". checking inside the ctools code, i found the error was being returned because the class "FeedsXPathParserXML" was undefined.
i found that adding 'file' => 'FeedsXPathParserXML.inc',
to the plugin definition stopped that. but that's a duplication of what's in 'handler'. so i'm not sure what would really be the solution here. (that's also why i don't think this is a duplicate of either #1038912: Error when switching to XML Parser or #1403164: Plugin XPath HTML parser of plugin type feeds:plugins points to nonexistent file)