Not able to drag terms and error code on save.

When autotag gives me the "discovered tags" and the two boxes to drag them around in, I am not able to drag them. Text gets highligted instead.

When I try to save anyway, using the top button (presumably supplied by autotag itself), I get this error (on an otherwise blank page):
Fatal error: [] operator not supported for strings in /var/www/virtual/server.cyberhus.dk/public_html/sikker_internet_dag_live/drupal/sites/all/modules/autotag/autotag.module on line 37

If I try to save using the standard save button below, I get this in a standard "oops, there was a problem box at the top of the right page):
warning: in_array() [function.in-array]: Wrong datatype for second argument in /var/www/virtual/server.cyberhus.dk/public_html/sikker_internet_dag_live/drupal/sites/all/modules/autotag/autotag.module on line 36.

I am a something of a newbie here, but autotag is obviously installed, and so is jquery (I get the one configuration option). There are no error messages for the installed components/modules - I have listed them all below, in case the versions might be relevant.

sky-6.x-2.x-dev.tar.gz
autotag-6.x-1.16.tar.gz
jquery_ui-6.x-1.2.tar.gz
jquery_update-6.x-1.1.tar.gz
jquery.ui-1.5.3.zip