Flash Player freezes during RTMP-Streaming of HD-Videos

We have an application (Online-TV Plus), which offers live channels and vods. some live channels are in high definition (codec: avc1, audio: mp41, videobitrate: 1500kbps, frame rate 50fps, 1280x720).
we didn't had any problems for the last months, but nowadays the live channels in hd suddenly freeze within the first 5-25min. we switched back to some older revisions of our flash player, but they have the same problem now...

after the channels freezes, we still can open our epg menu or change the volume of the flash player, but after clicking on an item, the box hang up and we have to restart the whole box.

there aren't any errors shown, in the logs, the whole file is attached, i just pointed out at which time the boxee crashed (Video was started at 17:53o'clock, so this time it made 10mi)

seems some problems with the new update (1.5.1.23735) or some problems with flash and the new update?!

Since i've spend the whole day on that issue, i hope you have some tipps/solutions for us?!
best,
k

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18:03:19.601 T:3010108304 M:446992384 DEBUG: CProcessSlowJob::DoWork - Enter function. [server=1][internet=1][IsStoped=0] (wdpslow)
18:03:19.601 T:3010108304 M:446992384 DEBUG: CProcessSlowJob::DoWork - Exit function. [server=1][internet=1] (wdpslow)
18:03:22.609 T:2971655056 M:446976000 DEBUG: Boxee: 21/03/12 17:03:22.6092#DEBUG#bxmetadataengine.cpp:379(EngineThread)#BXMetadataEngine::EngineThread, processing folders....(resolver)
18:03:29.711 T:3071379232 M:446951424 DEBUG: (dbg) FreeMem 436476/643508 Kb, FPS 60.0, CPU0: 92.3% (1.0%) Loader Q:[0] Textures:[212 (44.66 M)] SERVER: [67.225.149.139] ver: 1.5.1.23735-b6a5be1
18:03:29.711 T:3071379232 M:446951424 DEBUG: (dbg)
18:03:41.311 T:3071379232 M:446984192 DEBUG: (dbg) FreeMem 436508/643508 Kb, FPS 60.0, CPU0: 92.0% (1.3%) Loader Q:[0] Textures:[212 (44.66 M)] SERVER: [67.225.149.139] ver: 1.5.1.23735-b6a5be1
18:03:41.312 T:3071379232 M:446984192 DEBUG: (dbg)
18:03:52.904 T:3071379232 M:446730240 DEBUG: (dbg) FreeMem 436260/643508 Kb, FPS 60.0, CPU0: 92.1% (0.8%) Loader Q:[0] Textures:[212 (44.66 M)] SERVER: [67.225.149.139] ver: 1.5.1.23735-b6a5be1
18:03:52.905 T:3071379232 M:446730240 DEBUG: (dbg)

//BOXEE FREEZE

18:04:04.445 T:3071379232 M:449802240 DEBUG: (dbg) FreeMem 439260/643508 Kb, FPS 60.0, CPU0: 40.3% (0.4%) Loader Q:[0] Textures:[212 (44.66 M)] SERVER: [67.225.149.139] ver: 1.5.1.23735-b6a5be1
18:04:04.445 T:3071379232 M:449802240 DEBUG: (dbg)
18:04:15.973 T:3071379232 M:449794048 DEBUG: (dbg) FreeMem 439252/643508 Kb, FPS 60.0, CPU0: 40.6% (0.2%) Loader Q:[0] Textures:[212 (44.66 M)] SERVER: [67.225.149.139] ver: 1.5.1.23735-b6a5be1
18:04:15.974 T:3071379232 M:449794048 DEBUG: (dbg)
18:04:19.604 T:3010108304 M:449810432 DEBUG: CProcessSlowJob::DoWork - Enter function. [server=1][internet=1][IsStoped=0] (wdpslow)
18:04:19.605 T:3010108304 M:449810432 DEBUG: CProcessSlowJob::DoWork - Exit function. [server=1][internet=1] (wdpslow)
18:04:22.861 T:2971655056 M:449810432 DEBUG: Boxee: 21/03/12 17:04:22.8605#DEBUG#bxmetadataengine.cpp:379(EngineThread)#BXMetadataEngine::EngineThread, processing folders....(resolver)