Invalid token error

Hi there.

Occasionally I get an "invalid token" post-login on my bike store site.

I will try to supply more detailed info. about when I experience this but are there any immediate fixes you would suggest? I also get this when using the Game News template.

Thx

Hi,
please read this http://www.camcloud.com/blog/how-to-sol ... ith-joomla

Thanks Konrad.
I read this and checked the system cache plugin.
What this article doesn't tell me is whether the system cache should be enabled or not?
I do not have it enabled and I don't have the GK cache enabled either - should either or both of these be enabled?
thx