Date fields dissapear from node edit form and node display

Hi,

Im experiencing serious problems with the D5 version of the 'date' module: On several different sites, the CCK date fields dissapear from the node edit form and from the node display. Also, they don't shop up at ./admin/content/types anymore.

Troubleshooting:

* Update to the very latest -dev - Check, but no change
* Run update.php - Check, but no change
* Clear all your caches - Check, but no change
* Edit your date fields - the 'date' fields are not appearing on the Manage fields screen so I can not edit them
* Edit your views - (does not apply)
* If you still have trouble after that, see if your issue is already reported - Check, there are several related issues, e.g. a closed one, marked as 'fixed' (#365771: Disappearing dates because of Date Popup?) and one for the D6 version of the module (#581554: Dates sometimes disappear from views AND the node edit page). Also, there's ongoing trouble with updated sites (e.g. #326714: Date field disappears after 6.6 upgrade, but those issues are not limited to the 'Date' module)
* If you've done all that and you can't find a similar issue and things still aren't working, open a new issue and be sure to say you have already done all the troubleshooting steps - Check. so opening a new issue.

Thanks & greetings, -asb