When selecting a tile from a Library in the Add Theme dialog, I get the following error message:
"Error Library <name>.<ext> has no valid tiles for feature class..."
The path names of the Location field in the INFO table are relative or contain symbolic links.
Since Environment Variables are supported in the Library Definition file and in the INDEX.PAT file, they can be used to represent part of the path to the tiles.
For example, if the library is located at /disk1/esri/mylib/database, then you can substitute the variable $MYDIR for /disk1/esri. The Library Definition and the INDEX.PAT files now contain $MYDIR/mylib/database in their Location fields.