Just had same problem, tried 3 CMC unbranded, thought FU imgburn,, then tried a verb, the verb is burning happily at up to 10x.
I guess imgburn knows shitty discs when it see them... Won'tbother trying to be a cheapskate ever again , may use the remaining shitty CMC for backup or some wank.
Verb's are the masters, proof in case, for me anyway..
Rich