Glib's timeouts are based on real-time clock (g_get_current_time) which is not a good idea as the real time clock can be adjusted, resulting in an incorrect calculation of the elapsed time.
Generally all timer calculations should be based on a monotonic clock.

Have a look at this path:
http://gitorious.org/mer/glib2_0/commit/cc149fe934da510e95321526bbe7dce7a0580d74