If you're using the PCB without any enclosure
you need to take care where you hold the device and where you place it, in order to touch or obstruct critical parts like the antenna on the Bluetooth module (a possible cause).
Also, if you're using the beta version of OpenSignals (blue cloud logo), we suggest you try using our current version (green cloud logo) available here:http://bitalino.com/index.php/software
Another possible reason (more likely) is that the internal Bluetooth on your computer does not have good enough performance. This is a known and recurrent issue, for which we can do little more than suggesting our users to purchase a Bluetooth dongle known to work with BITalino:http://store.bitalino.com/index.php/standard-account-store#!/BITalino-proven-Bluetooth-v3-0-Adapter/p/35323608/category=6468352
BTW... don't let the outer shell of the dongle fool your. Although the look they have may be the same, the internals can be different and may not have good enough performance as well.
Hope any of these suggestions work out for you.
The BITalino Team