Invalid token ask about price form

[babu65]

Hi, I've searched in the forum and outside it, but  I can't find a solution about.
I'm working with Joomla 2.5.28 and VM 2.6.2 The PLG System cache is off the server cache in Joomla configuration is off the sessiontime life is 150 the upload max filesize is 20 M and post max size is 40 M.
When I try to send a mail by the button "ask about price" or Ask a question about the product" the box tell "Invalid token"

Somebody have a suggestion?

Thanks in advance