super drive in my imac.

[rdsii64]

My imac is a late 2009 24" 2.93 ghrtz with 4 gigs or ram. The super drive in my machine can burn double layer discs in both the +R and -R formats. Lately I have been having my burns hang up on either the lead in or the lead out. some times dialog box(sorry old windows term) says preparing and about minute or so time remaing and hangs there as well. sometimes I get a succsesfull burn. I have been using -R discs. I also have an external LG blu ray burner. When I burn a blu ray disc, all is well. When I burn a -R dvd I get these same issues. If I switch to a +R disc would this solve my issue or do I have a deeper problem.