Hierarchical select and Views: Filtering with Hierarchical select element: warning: Invalid argument supplied for foreach()...

Hello

I have a big problem with Hierarchical select.
I created a content type with a hierarchical select element with 2 stages.
I save the continents and the according countries in this element.

for example

Asia -> Japan,China etc...
Europe->Germany,France etc...

This part works fine. I can add new items to every stage and can select them directly. The data is saved correctly and the data is able to be displayed.
HS is configured to force the user to
A configuration entry is made for this hierarchical structure (Content Taxonomy as Node form).

Now I want to create a few views which should show the following stuff.

- show all entries of the continent (this is the root level in the taxonomy)
- show all entries of a country (this is the 1 sub level in the taxonomy)

So I created a view with glossary layout.
I set the argument (title)
I set the filter with the following details
- add the taxonomy term ID
- select the vocabolary which contains the continent/country terms
- selection type is set to hierarchical select
- set the operator to "is all of" (i use the german translation, so i don't know the correct english description for it) and then i select one of the hierarchical select-taxonomy entries like "Africa" or a a country from the next deeper stage.

When all is set and done, I only get a very big syntax error.

===============
    warning: Invalid argument supplied for foreach() in D:\xampp_alt\htdocs\drupal\modules\views\includes\handlers.inc on line 683.
    user warning: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ') ) count_alias' at line 4 query: SELECT COUNT(*) FROM (SELECT node.nid AS nid FROM node node INNER JOIN node_comment_statistics node_comment_statistics ON node.nid = node_comment_statistics.nid WHERE (node.type in ('kampfstile')) AND () ) count_alias in D:\xampp_alt\htdocs\drupal\modules\views\includes\view.inc on line 745.
    user warning: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ') ORDER BY node_title ASC LIMIT 0, 36' at line 8 query: SELECT node.nid AS nid, node.title AS node_title, node.type AS node_type, node.vid AS node_vid, node_comment_statistics.comment_count AS node_comment_statistics_comment_count FROM node node INNER JOIN node_comment_statistics node_comment_statistics ON node.nid = node_comment_statistics.nid WHERE (node.type in ('kampfstile')) AND () ORDER BY node_title ASC LIMIT 0, 36 in D:\xampp_alt\htdocs\drupal\modules\views\includes\view.inc on line 771.

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for every views filter a exposed filter is added automaticly. When I try to edit one of the exposed views filters the information from the taxonomy is available in the preview element.

I am not sure if Hierarchical select is creating this error or maybe Views itself produced this...
but I am not able to solve this problem on my own.

When I add an additional element in my content type to filter my entries then view really works but I really would like to see it working with taxonomy and hierarchical select...

Please help me to fix that problem. I really dont know why this error occured...