.mpg video files

Hi All,
My quite old DM8000HD has trouble recording .mpg files. Others like .avi etc just carry on recording/downloading but when I ask it to download a .mpg [usually better quality than .avi] it just switches off. However on several occasions I have then gone on to record the same thing in .avi and when I check the file on the disc both versions are there. OK - I can check both copies and they are complete with the .mpg file being much better quality. However, when I return to the .mpg file to play it a day or so later it is just not there. Any answers for this would be gratefully received. Cheers - Brain