"406 Not acceptable" Error when editing articles [SOLVED] - Joomla! Forum - community, help and support

dear all,

i run site on joomla 5.0.14 (on php 5.2.11 , apache/2.2.14 (unix) mod_ssl/2.2.14 openssl/0.9.8e-fips-rhel5 mod_bwlimited/1.4) , since point yesterday, error when editing articles via administration interface.

to precise: when click on "save", "close" or "apply" on editing page 406 not acceptable error following text:

not acceptable

an appropriate representation of requested resource /administrator/index.php not found on server.

additionally, 404 not found error encountered while trying use errordocument handle request.

it happens on articles, of them work fine. site this one , 1 of problematic articles this one. seems depend on content of article, creating new article withe same content produces same problem. new article short text works fine. other features of administrator backend seem work fine.

i have seen other people getting error, none of problems/solutions seem apply. administrator/index.php there , has proper access rights (644).

i'd grateful ideas...
gert

would rename, copy identical index.php file in place.

perhaps there hidden server attribute attached file?

have had problem, .htaccess file downloaded windows machine, edited, uploaded server
all permissions set on server, yet ignore file.

lucky me, had backup before edited on windows box.

good luck!