AEM CS5 problem with Mountain Lion

I am having exactly the same problem as

   http://forums.adobe.com/message/4681087

except mine occurs with AEM CS5 on OS X 10.8.

I use Extension Manager 5.0.3.4 on OS X 10.6.8 to create the .zxp package. This package installs fine on 10.5, 10.6 and 10.7. However, when installing on 10.8 (also with Extension Manager 5.0.3.4), I get the error

   "The file 'Macintosh HD:Users:username:Library:Caches:TemporaryItems:

     myPkg_mxi:myPlugin.InDesignPlugin:Resources' is missing. The extension

     will not be installed."

It looks like the symbolic link is flattened (badly).

Is anyone having this problem? Perhaps my .mxi is coded incorrectly for Mountain Lion? Does this line look wrong:

   <file source="myPlugin.InDesignPlugin" destination="$indesign/Plug-Ins/myFolder/"

     platform="mac" file-type="plugin" />

Any help would be greatly appreciated. TIA

Gary