I have had this problem 4 times already in the last hour with gnucleus after the update to 1.8.4, the software just crashes out of nowhere while searching for ultrapeers to connect to.
The Output of the error is this:

GNUCLEUS caused an invalid page fault in
module GNUCLEUS.EXE at 017f:004e7bd0.
Registers:
EAX=00000000 CS=017f EIP=004e7bd0 EFLGS=00010246
EBX=00000198 SS=0187 ESP=0083f92c EBP=0083fa4c
ECX=01190a00 DS=0187 ESI=00000000 FS=6567
EDX=00000000 ES=0187 EDI=00000000 GS=61ef
Bytes at CS:EIP:
89 5e 04 e8 d4 fe ff ff 57 56 ff 76 04 e8 03 fe
Stack dump:
ffffffff 00000000 011ea6a0 007105c4 00000001 5f100062 895a0002 17af1248 00000006 00080000 00025eb0 896c124d 16cf11f1 00000006 bff741f7 00000008

Sorry about the error dump but i didnt found any other link to where i could report a bug so i decided to post it here.