All FSX addon files are unaccessible after installing Zurich 1.3. The XML.dll has an "start/end tag mismatch" error.è
The error it's not in Zurich, you had the error before, and it has been caused by Wilco 737 PIC installer, that is known to corrupt the DLL.XML file.
As you can see, it's the 737 PIC line that has a missing closing tag:
<Name>FeelThere PIC737X Helper</Name>
See ? </Launch.Addon> here is missing.
This has been confirmed by PMDG as well:http://ops.precisionmanuals.com/wiki/How_to_Fix_Your_FSX_DLL.XML_File
NOTE: We have been able to confirm that the Wilco/FeelThere PIC 737 product is the prime offender when it comes to DLL.XML corruption on our customer's machines. This was verified by testing the installer and determining that it indeed edits the DLL.XML improperly, rendering it corrupted and on occasion useless to editors that may follow along later. We recommend that customers make a backup of their DLL.XML before installing these products.
I hear you asking: then why I only see this after installing Zurich ?
Reason is probably in the bold line above: since Wilco installer corrupt the DLL.XML, up to a point that it makes it difficult to edit even with text editors, it might be that it has the same adverse effect on our installer, that might become confused by the already corrupted file, just like an editor.
We'll need to add additional code in the installer, now, to defend ourselves from Wilco's mishaps...