Yes, the DVBworld box does unfortunately has this limitation or perhaps I should say the software that comes with the DVBworld box has this limitation. In this case it's not an operating system issue nor a filesystem issue, but seems to be a limitation of the DVBworld software itself. This is one of the reasons, I really wish we could get Tsreader support for this device. The software that comes with it, though usable most of the time, is not really that great and seems to have lots of little annoying quirks and bugs. I discovered a new one just today. Apparently on some signals with very high bitrate (>50Mbit) 4:2:2 Mpeg2 video, when you try to record it just gives you a 0 byte file as a result. It had no issues rendering the video (with the right codec and enough CPU muscle to handle it of course). So, it's not a bandwidth issue, but for some reason it just wouldn't record the stream. It would attempt to but produce a zero byte file. Anyway, this is just an example of how buggy and unpolished the DVBworld software really is. As for the 4gb recording limitation, my guess is someone used a 32 bit pointer in their code where they should've used something larger.
Anyway, in this case, it's not an operating system, file system, CPU, etc. issue. It's design flaw in the software. Instead it splits the recording into multiple files. What you can do if you really want one big file is use a piece of software like videoredo to join them into a single large file. For the time being I'm afraid that's the only option.
