Form problem

[eluser]dimis[/eluser]
I have a form and some inputs for languages.
For each language I have name[en],name[gr] etc.
These names as dynamically created from a database.
When I submit this form there is the message Disallowed Key Characters even I do not assign the post elements.
How can I resolve it or how I can pass these elements that i can not create them statically?