"What's strange is that it has worked with the same conditions in the past."
Maxell 8X +R were until recently manufactured by Maxell (great quality). Now they outsource to Ritek and most of these discs are actually Ritek R03 media (variable quality, from very good to mediocre depending on batches, like almost all DVDR Ritek productions nowadays, sadly ).
This may well be the source of your problem... You can check what your discs really are with CD Speed. If you like +R, follow Alex's advice and try discs with a RICOHJPNR02 mediacode.
For -R 8X medias, the peace-of-mind choice is Verbatim (MCC 02RG20), cheaper than Taiyo Yuden (king of quality) and just as reliable. But I have no experience with the Toshiba player.