Callback when busy - Queue problem

hello
I’ve configured callback when busy -> http://www.osslab.org.tw/index.php?title=實驗專案/Asterisk/Tips/忙線回撥-Busy_CallBack

It is working fine, but I have problem about queue.

when all agents are busy it reports busy callback instead of queue the call.

any ideas?

my queue number is 1999 and i’m calling from 1804
here is debug information:

– dialparties.agi: Filtered ARG3:
> dialparties.agi: NODEST: 1999 blkvm enabled macro already in dialopts: trM(auto-blkvm)
> dialparties.agi: NODEST: 1999 blkvm enabled macro already in dialopts: trM(auto-blkvm)
== Manager ‘admin’ logged off from 127.0.0.1
– AGI Script dialparties.agi completed, returning 0
– Executing [s@macro-dial:4] NoOp(“Local/1887@from-internal-25e0,2”, “Returned from dialparties with no extensions to call and DIALSTATUS: BUSY”) in new stack
– Executing [s@macro-exten-vm:10] GotoIf(“Local/1887@from-internal-25e0,2”, “0?exit|return”) in new stack
– Executing [s@macro-exten-vm:11] Set(“Local/1887@from-internal-25e0,2”, “SV_DIALSTATUS=BUSY”) in new stack
– Executing [s@macro-exten-vm:12] GosubIf(“Local/1887@from-internal-25e0,2”, “0?docfu|1”) in new stack
– Executing [s@macro-exten-vm:13] GosubIf(“Local/1887@from-internal-25e0,2”, “0?docfb|1”) in new stack
– Executing [s@macro-exten-vm:14] Set(“Local/1887@from-internal-25e0,2”, “DIALSTATUS=BUSY”) in new stack
– Executing [s@macro-exten-vm:15] NoOp(“Local/1887@from-internal-25e0,2”, “Voicemail is novm”) in new stack
– Executing [s@macro-exten-vm:16] GotoIf(“Local/1887@from-internal-25e0,2”, “1?s-BUSY|1”) in new stack
– Goto (macro-exten-vm,s-BUSY,1)
– Executing [s-BUSY@macro-exten-vm:1] NoOp(“Local/1887@from-internal-25e0,2”, “Extension is reporting BUSY and set automatical CallBack”) in new stack
– Executing [s-BUSY@macro-exten-vm:2] GotoIf(“Local/1887@from-internal-25e0,2”, “0?exit|1”) in new stack
– Executing [s-BUSY@macro-exten-vm:3] ChanIsAvail(“Local/1887@from-internal-25e0,2”, “SIP/1887|s”) in new stack
– Executing [s-BUSY@macro-exten-vm:4] GotoIf(“Local/1887@from-internal-25e0,2”, “0?s-NOANSWER|1”) in new stack
– Executing [s-BUSY@macro-exten-vm:5] Read(“Local/1887@from-internal-25e0,2”, “digit|busy-callback|1|i|3”) in new stack
– Accepting a maximum of 1 digits.
– <Local/1887@from-internal-25e0,2> Playing ‘busy-callback’ (language ‘en’)
– Local/1887@from-internal-25e0,1 answered SIP/1804-082f88b8

No Ideas?