Problen to call extensions

This is my first try to install asterisk - after several tries i manage to get it “work” with freepbx, i created extensions but when i am trying to call one ext to other i get those errors

Connected to Asterisk 1.4.10 currently running on pc2 (pid = 6400)
[Oct 21 15:19:22] NOTICE[6411]: chan_sip.c:12308 handle_response_peerpoke: Peer '2000' is now Reachable. (7ms / 2000ms)
[Oct 21 15:20:18] WARNING[8420]: file.c:563 ast_openstream_full: File cannot-complete-as-dialed does not exist in any format
[Oct 21 15:20:18] WARNING[8420]: file.c:813 ast_streamfile: Unable to open cannot-complete-as-dialed (format 0x4 (ulaw)): No such file or directory
[Oct 21 15:20:18] WARNING[8420]: app_playback.c:437 playback_exec: ast_streamfile failed on SIP/2000-08207a30 for silence/1&cannot-complete-as-dialed&check-number-dial-again|noanswer
[Oct 21 15:20:18] WARNING[8420]: file.c:563 ast_openstream_full: File check-number-dial-again does not exist in any format
[Oct 21 15:20:18] WARNING[8420]: file.c:813 ast_streamfile: Unable to open check-number-dial-again (format 0x4 (ulaw)): No such file or directory
[Oct 21 15:20:18] WARNING[8420]: app_playback.c:437 playback_exec: ast_streamfile failed on SIP/2000-08207a30 for silence/1&cannot-complete-as-dialed&check-number-dial-again|noanswer

Can anybody help me on this?

i got also those errors on freepbx, i don’t know if this is related…

Retrieve conf failed to copy file(s) from a module's agi-bin dir: copy(/usr/share/asterisk/agi-bin/list-item-remove.php): failed to open stream: Permission denied copy(/usr/share/asterisk/agi-bin/fixlocalprefix): failed to open stream: Permission denied copy(/usr/share/asterisk/agi-bin/dialparties.agi): failed to open stream: Permission denied copy(/usr/share/asterisk/agi-bin/checksound.agi): failed to open stream: Permission denied copy(/usr/share/asterisk/agi-bin/recordingcheck): failed to open stream: Permission denied copy(/usr/share/asterisk/agi-bin/enumlookup.agi): failed to open stream: Permission denied copy(/usr/share/asterisk/agi-bin/directory): failed to open stream: Permission denied

and suddenly everything worked… without changing anything!!