Version:           unspecified (using KDE 4.6.0) 
OS:                Linux

Subj. I did "strace ark somerararchive.rar" and got this:
poll([{fd=7, events=POLLIN|POLLOUT}], 1, -1) = 1 ([{fd=7, revents=POLLOUT}])
writev(7, [{"&\0\2\0\214\1\0\0", 8}, {NULL, 0}, {"", 0}], 3) = 8
poll([{fd=7, events=POLLIN}], 1, -1)    = 1 ([{fd=7, revents=POLLIN}])
read(7, "\1\1\24\251\0\0\0\0\214\1\0\0z\20\306\1u\2\10\0u\2\10\0\20\0\0\0\0\0\0\0", 4096) = 32
read(7, 0x8085b90, 4096)                = -1 EAGAIN (Resource temporarily unavailable)
read(7, 0x8085b90, 4096)                = -1 EAGAIN (Resource temporarily unavailable)
read(7, 0x8085b90, 4096)                = -1 EAGAIN (Resource temporarily unavailable)

This part repeats many times. 
P.S. Krusader opens this archive and asks password normally.

Reproducible: Always