I was playing arround with the V5 demo and the "cube w shadow.veg" project, and when I adjusted the tracks' height using the scrollbar thingy on the right I got this :
(XP pro, 512 mb ram, Pentium4 3 ghz)

Sony Vegas 5.0
Version 5.0a (Build 134)
Exception 0xC0000005 (access violation) READ:0x5901000 IP:0x73B52591
In Module 'MSVFW32.dll' at Address 0x73B50000 + 0x2591
Thread: GUI ID=0xF80 Stack=0x12F000-0x130000
Registers:
EAX=05a0051c CS=001b EIP=73b52591 EFLGS=00010206
EBX=058c0800 SS=0023 ESP=0012f1d8 EBP=001eca50
ECX=0166ff47 DS=0023 ESI=05901000 FS=003b
EDX=11c40020 ES=0023 EDI=11c80820 GS=0000
Bytes at CS:EIP:
73B52591: F3 A5 8B C8 83 E1 03 F3 ........
73B52599: A4 8B 03 03 C3 89 85 E0 ........
Stack Dump:
0012F1D8: 0012F274 00030000 + FF274
0012F1DC: 00000028
0012F1E0: 001ECA50 00140000 + ACA50
0012F1E4: 058C0800 05880000 + 40800
0012F1E8: 00009200
0012F1EC: 00008000
0012F1F0: 047868DD 01740000 + 30468DD
0012F1F4: 00000000
0012F1F8: 00565074 00400000 + 165074 (vegas50.exe)
0012F1FC: 058B4F1C 05880000 + 34F1C
0012F200: 77E55A65 77E40000 + 15A65 (kernel32.dll)
0012F204: 00000A68
0012F208: 001ECA50 00140000 + ACA50
0012F20C: 047868C0 01740000 + 30468C0
0012F210: 001ED000 00140000 + AD000
0012F214: 001ED000 00140000 + AD000
> 0012F224: 73B5197E 73B50000 + 197E (MSVFW32.dll)
> 0012F254: 004848F7 00400000 + 848F7 (vegas50.exe)
0012F258: 058D7EB0 05880000 + 57EB0
0012F25C: 0012F284 00030000 + FF284
0012F260: 00000000
0012F264: 00000000
> 0012F278: 004863B8 00400000 + 863B8 (vegas50.exe)
0012F27C: 001ECA50 00140000 + ACA50
0012F280: BE011339
0012F284: 00000298
0012F288: 0000015B
> 0012F2BC: 00530020 00400000 + 130020 (vegas50.exe)
0012F2C0: 00000000
0012F2C4: 00000000
> 0012F2C8: 00440020 00400000 + 40020 (vegas50.exe)
0012F2CC: 00000001
0012F2D0: 00000006
0012F2D4: 00000000
0012F2D8: 00000000
> 0012F338: 05F5DE8F 05E10000 + 14DE8F (sftrans1.dll)
- - -
0012FFF0: 00000000
0012FFF4: 00000000
0012FFF8: 007287E0 00400000 + 3287E0 (vegas50.exe)
0012FFFC: 00000000