Trouble with getbyhostname()

Hi,
I am having trouble with getbyhostname().I works sometimes but on
other occasions it crashes.
IPADDRESS is a string say "192.123.12.1"

(gdb)
 Client::SendSocket (this=0xbfa9493c, QuerBuf=@[EMAIL PROTECTED]
    IPADDRESS=@[EMAIL PROTECTED]
) at Client.cc:141
141             h = gethostbyname(IPADDRESS.c_str());
(gdb)
*** glibc detected *** /home/workspace/DNSResolver1/checkstring:
free(): invalid next size (normal): 0x0804eb38 ***
======= Backtrace: =========
/lib/tls/i686/cmov/libc.so.6[0xb7db1d65]
/lib/tls/i686/cmov/libc.so.6(cfree+0x90)[0xb7db5800]
/lib/tls/i686/cmov/libc.so.6(fclose+0x134)[0xb7da06f4]
/lib/tls/i686/cmov/libc.so.6[0xb7e2a73d]
/lib/tls/i686/cmov/libc.so.6(__res_ninit+0x25)[0xb7e2ae65]
/lib/tls/i686/cmov/libc.so.6(__res_maybe_init+0x7b)[0xb7e2c30b]
/lib/tls/i686/cmov/libc.so.6(__nss_hostname_digits_dots+0x2d)
[0xb7e2dcdd]
/lib/tls/i686/cmov/libc.so.6(gethostbyname+0x9a)[0xb7e3227a]