Undefined variable

Not sure if this one goes here or on 'webform validation'

I'm getting this error message:

Notice: Undefined variable: checkboxrules in clientside_validation_webform_add_webform_validation() (line 229 of C:\www\arlbergextreme\sites\all\modules\clientside_validation\clientside_validation_webform\clientside_validation_webform.module).
Warning: Invalid argument supplied for foreach() in clientside_validation_webform_add_webform_validation() (line 229 of C:\www\arlbergextreme\sites\all\modules\clientside_validation\clientside_validation_webform\clientside_validation_webform.module).

After I have added a plain text validation to a text field, the above error messages shows up, if I delete the validation rule, it doesn't show.

I have enabled all the Clientside Validations modules, the Field Validation module and of course the Web Form Validation module.

Any suggestions?