Yes,
it is a bug in 1.8 (having a typo in the json include path). If you have PHP older than 5.2 the json functions are not included in the PHP and myDBR resorts to included JSON.php. The bug is fixed in upcoming version, but you have few options to go around it for now:
1) Create a directory /var/www/html/mydbrlib and copy the JSON.php from mydbr/lib/JSON.php to it
2) Install json using PECL
3) Update the PHP
Do believe the tirst one would be the easiest.
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myDBR Team