Blank DVD discs that used to be recognised are... (by 2 users)

I've found that once a disk is formatted in certain formats with a pc it prevents the LG from reading it.  Format it again in the LG (if you can!) or use the pc to format it using the UDF1.5 setting in a pc (which sort of resets it so the LG can at least see it as an unused disc again). 

All in all I have found my RH19991H really confusing as far as disk initialization and formatting and finalizing is concerned.  Sometimes you can select to finalize a +-rw dvd and sometimes not (the latter is the the case according to the manual) and sometimes I can select the format mode and sometimes not.  Sometimes the machine auto finalizes the dvd+-rw (the way it should be says the manual) and sometimes it does not and then I cannot use it in the pc.  I have also created some disks with DivX files and was able to play them in the LG and then using the same pc, same type of discs, same video editing software and same settings created other DivX files I could not play on the LG.  It seems the software on the machine needs some work...