When change template : Your browser sent a request that this server could not underst
 

when try to change forumhome template in certain style I get :

however the rest of styles and templates of this style are changed normally

That usually happens when the URL that goes to the browser is misspelled or malformed so the request doesn't match the standard syntax. Check the browser input box to see it you can see a misspelling or something when you try to bring up that page.

I am sure of spelling
I come to this error after choosing edit templates from my admin cp
so there is no error in writing

Is this only with a specific edit (can you save the template without any changes)?

Also this could be caused by mod_security or Suhosin, is any of thatinstalled at your server?

it is for specific template of specific style, any edit I get that message (not specific edit)
I am not using one of above mods

Those are not vB modifications (just in case you misunderstood that).

Can you try to up your PHP memory limit?

how to do that?

--------------- Added [DATE]1235055117[/DATE] at [TIME]1235055117[/TIME] ---------------

by the way I noticed in general large templates as showthread and forumhome cannot be edited
small templates as postbit and tagbit are edited normally

Can you go to vbulletin options --> show all settings and try to save all settings at once, does that work?

If it doesn't please check and verify that your server is running modsecurity, you can verify that its running modsecurity by viewing your php info, it should be listed under apache2handlers Loaded Modules box.

Example:

no it does not
how to do that
I am running admin panel
how to know apache2handelers?

thanks for help

admincp --> maintenance --> View PHP info