Will not accept DVD RW disks except the LG variety

After reading the manual about ten times realised that this particular machine will only accept -R, or -RW's. We've been trying to work with +R and +RW's ... On one occasion after formatting the disk on a computer (+RW) placed it in machine .. It rejected it... but would not eject it and in consequence we had to literally dismantle the machine to physically remove the disk!!!!

Thanks for your time!

Mariner10