Create New User Fails

For no apparent reason my Gallery installation has suddenly began to fail when attempting to add a new user. It worked fine for the first 50 odd users but now I am getting an error storage failure.

I have copied the error code below. Any help at all or pointers would be great.

Error (ERROR_STORAGE_FAILURE)
in modules/core/classes/GalleryStorage/GalleryStorageExtras.class at line 1113 (GalleryCoreApi::error)
in modules/core/classes/GalleryStorage.class at line 533 (GalleryStorageExtras::removeMapEntry)
in modules/core/classes/GalleryCoreApi.class at line 2935 (GalleryStorage::removeMapEntry)
in modules/core/classes/helpers/GalleryItemHelper_medium.class at line 853 (GalleryCoreApi::removeMapEntry)
in modules/core/classes/helpers/GalleryItemHelper_medium.class at line 873 (GalleryItemHelper_medium::invalidateDescendentCountCaches)
in modules/core/classes/helpers/GalleryEventHelper_simple.class at line 59 (GalleryItemHelper_medium::handleEvent)
in modules/core/classes/GalleryCoreApi.class at line 2238 (GalleryEventHelper_simple::postEvent)
in modules/core/classes/GalleryItem.class at line 440 (GalleryCoreApi::postEvent)
in modules/core/classes/GalleryAlbumItem.class at line 256 (GalleryItem::save)
in modules/core/classes/helpers/GalleryItemHelper_advanced.class at line 247 (GalleryAlbumItem::save)
in modules/core/classes/GalleryCoreApi.class at line 1646 (GalleryItemHelper_advanced::createAlbum)
in modules/useralbum/classes/UserAlbumHelper.class at line 57 (GalleryCoreApi::createAlbum)
in modules/useralbum/module.inc at line 154 (UserAlbumHelper::createUserAlbum)
in modules/core/classes/helpers/GalleryEventHelper_simple.class at line 59 (UserAlbumModule::handleEvent)
in modules/core/classes/GalleryCoreApi.class at line 2238 (GalleryEventHelper_simple::postEvent)
in modules/core/classes/GalleryEntity.class at line 285 (GalleryCoreApi::postEvent)
in modules/core/classes/GalleryUser.class at line 218 (GalleryEntity::save)
in modules/core/AdminCreateUser.inc at line 80 (GalleryUser::save)
in main.php at line 250 (AdminCreateUserController::handleRequest)
in main.php at line 104
in main.php at line 88
System Information
Gallery version 2.3
PHP version 5.2.6 cgi-fcgi
Webserver Apache/1.3.37 (Unix) mod_throttle/3.1.2 FrontPage/5.0.2.2635 mod_ssl/2.8.28 OpenSSL/0.9.8b
Database mysqli 4.1.20-max-log
Toolkits ImageMagick, Gd
Operating system Linux

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