It seems the URLs are created and/or rendered incorrectly. This issue tends to occur when multiple environments use the same database where the hostnames differ. Or rather when in one environment the default project is JAS and in the other it isn't.
Currently the page browser logic in the lister plugin only remembers the sorting and the filters in rewrite mode. It should use a more generic approach where it reads the relevant filters from the Data object and use that.
Additionally it's probably a good idea to split off the page browser logic in the lister plugin from the output function so other plugins can easily reuse this logic.
Convert by: JAS13OCT014
The file (and image) field should get an additional field for the MD5 hash. The /files/ would then need a "MD5" variable that would download a "text/plain" file with the hash as content. The filename can be generated based on the original filename and a .md5 suffix (filename.ext.md5).
Note that it's probably wise to add a MD5 property to the file/image fields to allow it to be enabled/disabled.
If an error occurs when move a "list" of items to another category it doesn't get the relevant data the next time the CMS is displayed.
Presumably this is because catnr is replaced catnr[0], catnr[1], etc in the (hidden) CMS fields