Hang up detection: Subject changed from - IVR Delay

Hi
I have realized my IVR takes approx 45 second to reinitialize.
Here is the scenario, in IVR created main menu which has language prompt, as “1 pour Français, 2 for English” that directs to 2 other IVR,s that redirects to 4 extentions. when there is an inbound call after all prompts direct to proper extension than after terminating the call and hang-up all works fine except if within 30 seconds another call enters IVR doesn’t kick, callers will ring until they fed-up, have to wait around 45 second to restart prompting, wondering how I fix that.
Hard to blame my server:
GenuineIntel Intel® Pentium® 4 CPU 3.20GHz
1 gig ram, hard drive 40G 8% used

Thanks