Invalid free/delete

While debugging with valgrind, I always receive the following error
message.

==30439== Invalid free() / delete / delete[]
==30439== at 0x400448F9: free (vg_clientfuncs.c:180)
==30439== by 0x421136CD: (within /lib/i686/libc-2.2.5.so)
==30439== by 0x4207F852: (within /lib/i686/libc-2.2.5.so)
==30439== by 0x400451FC: vgPlain___libc_freeres_wrapper
(vg_clientfuncs.c:585)
==30439== by 0x4202BCC9: (within /lib/i686/libc-2.2.5.so)
==30439== by 0x42017592: (within /lib/i686/libc-2.2.5.so)
==30439== by 0x80491E1: (within
/home/chatgris/code/mastermailings/code/daemons/email_manager/email_manager.o)
==30439== Address 0x402544D0 is not stack'd, malloc'd or free'd

I compiled a program with -L/usr/local/pgsql/lib -lpq

and then ran it with valgrind to check for memory leaks.

unfortunately, I don't know enough about pg to really understand what
could be casuing this, but problems like this can easily lead to
infrequent segfaults =).

Josh.