Hi Skinamp
I googled for a Hyundai MMPlayer but only find automotive players. Would be interested in reading the functional spec for the MMPlayer you are using. Paste a url if you have one.
In the meantime let me describe what I'm doing.
Setup2 USB drives (1 TB each) attached to a Linksys NSLU2 NAS controller aka a "Slug" on the LAN.
NSLU2s w/USB Drives hold my ISO files.
Headless desktop PC on the LAN attached to a projector (could also use a TV monitor).
Virtual DVD drive running on the PC.
Use location field in Coollector to store path to the ISO file. e.g. \\192.168.1.xx\disk 1\filename.iso
UsageFire up the projector select the PC as the input source. Open Coollector on the big screen and choose a movie. Click the play button in Coollector and click the file path/name. This causes the PC to load the ISO from the NAS location into the virtual dvd drive. That auto launches the PC's DVD media player.
When the virtual drive "loads" the ISO from the NAS it does not load the entire 5 or 8 GB file. It fetches a few blocks of data at a time so the streaming and buffering is managed by the SMB protocol (Samba). This is running across a 100Mb wired LAN but I've also tested it on G wireless and it worked ok with occasional hitches. A faster WLAN probably would work even better.
Possible SolutionIf your MMPlayer can read the files of an unpacked ISO then you could leave your files in ISO format on one or more USB drives attached to the PC. On the PC you would load (actually mount) an ISO into the virtual DVD drive. Then point the MMPlayer at the virtual drive where it will see an unpacked ISO.
USB 2.0 transfer rate is 480Mbps so I'm quite sure that is not going to be a bottleneck.
What is unclear to me is how your MMPlayer handles the data it is reading from your PC. If it can read the data but the wireless is too slow then it maybe time to punch a hole in wall. Use a short bit of PVC pipe cut flush with either side of the wall to give it a nice finished look.

Let me know if this helps.
Regards,
~KnoWei