New DVD burning problems

I have Memorex 4x and PENGO 4x media. Works good, i have very good DVD backups (Anydvd, Pinacle Instant Copy, the best).

Everything is ok, but NOW i have very big problems burning at 4x!!!

If i burn at 2x or 2.4, no problems (testing using DVd decripter ISO mode and Pinacle Direct Burning).

If i write at 4x… i lost EVERY dvd disk i use… the burn process is stoped at 93 - 99% with a strange errors…

is my dvd writer damaged? any solution or recomendation please?

What strange errors might those be? What is your drive?

Also keep in mind that there are better media out there. It wouldnt hurt trying some other media out and see if the problem is media related.