Error setting default template in MIGXdb child resource

I'm following the guide here: http://rtfm.modx.com/extras/revo/migxdb/migxdb.tutorials/migxdb.manage-child-resources-in-a-grid-tv-with-help-of-migxdb#MIGXdb.ManageChild-Resourcesinagrid-TVwithhelpofMIGXdb-SettheTemplateforourchildren
but when I click done on step 6 for the final time I get the following error:

Unexpected token <:
Not Acceptable
An appropriate representation of the requested resource /assets/components/migx/connector.php could not be found on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

Is this a bug, or something I've done wrong?

MODX Revolution 2.2.13-pl
PHP 5.3.28 [ed. note: chr.s last edited this post 12 years, 6 months ago.]

I've seen something like that reported by others.
They did also talk about some server-settings, had allready googled a bit, but couldn't find it.

Perhaps here is something, which can help
https://www.google.de/search?q=mod+secure+Not+Acceptable&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:de:official&client=firefox-a&gfe_rd=cr&ei=SKocU--_Fcr5swb-iYGYBg

OK, so I added the following the my .htaccess file:



Now when I click done on the final dialog box, another narrow one appears with a site preview displayed. When I click OK, it closes and the manager looks very buggy indeed.

The attached image is of the subsequent full window.

Edit: Even commenting out the lines in .htaccess, I'm still getting this weird behaviour. [ed. note: chr.s last edited this post 12 years, 6 months ago.]

this still must be something server-specific or some file-permission-issue.
If the response returns your home-page, you may have not defined a not-found or error-page and modx does return your home-page on errors.

Indeed, it was a server issue.
The guys over at Nethosted got it fixed.