Internal server error 500 after signup

Looks like I get the same error:

Notice: Undefined index: sv i _cck_signup_validate_signup_node() (rad 103 av [..]/public_html/sites/all/modules/cck_signup/cck_signup.module).

Also got this:

Notice: Undefined index: field_anmalan i _cck_signup_validate_signup_node() (rad 103 av [..]/public_html/sites/all/modules/cck_signup/cck_signup.module).

And to give you some more info. I've set up three types of events with two types of signup (one to actually signup for two of the events and one to unsignup for another type of event). The first error message came unsigning up and the second from signing up.

I get the same error when sign up for an event is done. The signup itself is working fine it's just this strange error message. As far as I understand the error comes up as soon as the check is done if the event is not already closed, in the past ect. Could be wrong tho.

500 error when looking I click the "signups" tab on the node (logged in as admin)

error log:

Cannot access empty property in /home/robbie/www.yourcolony.com/html/sites/all/modules/signup/views/handlers/signup_h... on line 23, referer: http://www.ypco.org/node/260/edit?destination=node%2F265&render=overlay

I see the last comment here is six months old, but I still get this error in Alpha5. In a similar issue is described that a certain value is called directly through an array, including a language key. This is where things go wrong.

Unlike in D6, in D7 it's bad practice to get a value directly like this. A blog post by ComputerMinds explains it better than I can do.

Duplicate of #1335492: Undefined index in cck_signup.module?