Thanks David, here's the output from strace:
kev@kh-debian:~$ sudo mkiss /tmp/kisstnc /dev/pts/3
mkiss: open: Permission denied
kev@kh-debian:~$ sudo strace mkiss /tmp/kisstnc /dev/pts/3
execve("/usr/local/sbin/mkiss", ["mkiss", "/tmp/kisstnc", "/dev/pts/3"], [/* 14 vars */]) = 0
brk(0)????????????????????????????????? = 0x11be000
access("/etc/ld.so.nohwcap", F_OK)????? = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f594967b000
access("/etc/ld.so.preload", R_OK)????? = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=109904, ...}) = 0
mmap(NULL, 109904, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f5949660000
close(3)??????????????????????????????? = 0
access("/etc/ld.so.nohwcap", F_OK)????? = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/tls/x86_64/libax25.so.1", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat("/lib/x86_64-linux-gnu/tls/x86_64", 0x7fff60a9e070) = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/tls/libax25.so.1", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat("/lib/x86_64-linux-gnu/tls", 0x7fff60a9e070) = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/x86_64/libax25.so.1", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat("/lib/x86_64-linux-gnu/x86_64", 0x7fff60a9e070) = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libax25.so.1", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat("/lib/x86_64-linux-gnu", {st_mode=S_IFDIR|0755, st_size=12288, ...}) = 0
open("/usr/lib/x86_64-linux-gnu/tls/x86_64/libax25.so.1", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat("/usr/lib/x86_64-linux-gnu/tls/x86_64", 0x7fff60a9e070) = -1 ENOENT (No such file or directory)
open("/usr/lib/x86_64-linux-gnu/tls/libax25.so.1", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat("/usr/lib/x86_64-linux-gnu/tls", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
open("/usr/lib/x86_64-linux-gnu/x86_64/libax25.so.1", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat("/usr/lib/x86_64-linux-gnu/x86_64", 0x7fff60a9e070) = -1 ENOENT (No such file or directory)
open("/usr/lib/x86_64-linux-gnu/libax25.so.1", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat("/usr/lib/x86_64-linux-gnu", {st_mode=S_IFDIR|0755, st_size=69632, ...}) = 0
open("/lib/tls/x86_64/libax25.so.1", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat("/lib/tls/x86_64", 0x7fff60a9e070) = -1 ENOENT (No such file or directory)
open("/lib/tls/libax25.so.1", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat("/lib/tls", 0x7fff60a9e070)??????? = -1 ENOENT (No such file or directory)
open("/lib/x86_64/libax25.so.1", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat("/lib/x86_64", 0x7fff60a9e070)???? = -1 ENOENT (No such file or directory)
open("/lib/libax25.so.1", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260$\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=144600, ...}) = 0
mmap(NULL, 2136192, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f5949253000
mprotect(0x7f594925c000, 2097152, PROT_NONE) = 0
mmap(0x7f594945c000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x9000) = 0x7f594945c000
close(3)??????????????????????????????? = 0
access("/etc/ld.so.nohwcap", F_OK)????? = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\34\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1738176, ...}) = 0
mmap(NULL, 3844640, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f5948ea8000
mprotect(0x7f594904a000, 2093056, PROT_NONE) = 0
mmap(0x7f5949249000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1a1000) = 0x7f5949249000
mmap(0x7f594924f000, 14880, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f594924f000
close(3)??????????????????????????????? = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f594965f000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f594965e000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f594965d000
arch_prctl(ARCH_SET_FS, 0x7f594965e700) = 0
mprotect(0x7f5949249000, 16384, PROT_READ) = 0
mprotect(0x7f594967d000, 4096, PROT_READ) = 0
munmap(0x7f5949660000, 109904)????????? = 0
brk(0)????????????????????????????????? = 0x11be000
brk(0x11df000)????????????????????????? = 0x11df000
open("/var/lock/LCK..kisstnc", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/var/lock/LCK..3", O_RDONLY)????? = -1 ENOENT (No such file or directory)
open("/tmp/kisstnc", O_RDWR|O_NONBLOCK) = -1 EACCES (Permission denied)
dup(2)????????????????????????????????? = 3
fcntl(3, F_GETFL)?????????????????????? = 0x8002 (flags O_RDWR|O_LARGEFILE)
fstat(3, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 0), ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f594967a000
lseek(3, 0, SEEK_CUR)?????????????????? = -1 ESPIPE (Illegal seek)
write(3, "mkiss: open: Permission denied\n", 31mkiss: open: Permission denied
) = 31
close(3)??????????????????????????????? = 0
munmap(0x7f594967a000, 4096)??????????? = 0
exit_group(1)?????????????????????????? = ?
+++ exited with 1 +++
