Strange fatal error when submitting a form!

[eluser]Isos[/eluser]

Code:

Fatal error: Call to undefined function get_instance() in /Natalisushka/srv/www/UnderConstruction/client-core.com/kernel/libraries/Input.php on line 855

Why? I have a very normal form with validation setting rules and fields, inserting values into the database upon success in running validation.!!

[eluser]tonanbarbarian[/eluser]
I think you are going to need to post a lot more code for someone to work this out.

However my first though is are you running the code in CI or trying to do something stand alone, because there is no way that get_instance would not be declared if the code is running inside CI

[eluser]JoostV[/eluser]
It could be XSS filtering playing up. Here's the solution: http://ellislab.com/forums/viewthread/60481/#297369