Illegal String Offset Issue

Within the Admin Backend I am receiving the following Warnings:

Warning: Illegal string offset ‘expiration’ in /home/xxxx/public_html/mywebsite/wp-content/plugins/idx-broker-platinum/idx/idx-api.php on line 155
Warning: Cannot modify header information – headers already sent by (output started at /home/xxxx/public_html/mywebsite/wp-content/plugins/idx-broker-platinum/idx/idx-api.php:155) in /home/xxxx/public_html/mywebsite/wp-includes/functions.php on line 6270

I recently moved the site from local development over to a live server. Perhaps there is something going on with that? Any ideas? Thanks!