Well, Ok I tried "bpx b3fcd787" in sice 4.27, I didn't get that error message. But if you "d b3fcd787", it's all '?', which means non-present memory and it's not in PTE table. livekd reports same idt int3 handler address as sice on my computer. I'll take a look at the source code later, but there is another thing fishy about the sdt dumper because all its b3fcxxxx addresses show granuality = 1 (4kbytes per descriptor limit) while the good 80xxxxxx ones show granuality = 0.