Parse error: syntax error, unexpected '=', expecting ')'

I'm getting the following error after upgrading to 5.x-3.0-alpha5:

Parse error: syntax error, unexpected '=', expecting ')' in (...) spam/modules/spam_comment.inc on line 48

I re-installed the module including the tables but it always stays the same: Right after enabling the module (i.e. the Spam API part is enough) I get the message above. I'm running Drupal 5.8.