death_au on "[Plugin: Urban Push] Warning: strstr() [function.strstr]: Empty delimiter"

Urban Push seems to be giving me the warning:
Warning: strstr() [function.strstr]: Empty delimiter in [Redacted]\wp-content\plugins\urban-push\urbanpush.php on line 67
on the create post page. And when I try to publish a post with a push notifications I get more of the same:

Warning: strstr() [function.strstr]: Empty delimiter in [Redacted]\wp-content\plugins\urban-push\urbanpush.php on line 67

Warning: strstr() [function.strstr]: Empty delimiter in [Redacted]\wp-content\plugins\urban-push\urbanpush.php on line 74

Warning: strstr() [function.strstr]: Empty delimiter in [Redacted]\wp-content\plugins\urban-push\urbanpush.php on line 83

Warning: strstr() [function.strstr]: Empty delimiter in [Redacted]\wp-content\plugins\urban-push\urbanpush.php on line 67

Warning: strstr() [function.strstr]: Empty delimiter in [Redacted]\wp-content\plugins\urban-push\urbanpush.php on line 74

Warning: Cannot modify header information - headers already sent by (output started at C:\xampp\htdocs\WordpressTest\wp-content\plugins\urban-push\urbanpush.php:67) in [Redacted]\wp-includes\pluggable.php on line 881

And I get not push notification sent.
Is there an easy fix for this?

http://wordpress.org/extend/plugins/urban-push/