.NET Runtime 2.0 Error

Hi, please help,

I have visual basic express beta 2 and .net 2.0
What I have written appears to work fine. It may run fine for an hour or 2, then
some of the common controls on the main form appear to behave strangely. EG:
three combo boxes, the actual drop down arrow turned in a number 6 on all three. Then the program terminates, with the following error.

Event Type: Error
Event Source: .NET Runtime 2.0 Error Reporting
Event Category: None
Event ID: 5000
Date:  15/07/2005
Time:  23:40:50
User:  N/A
Computer: IBM-D90911CBD03
Description:
EventType clr20r3, P1 aalister.exe, P2 1.0.0.0, P3 42d7f9e2, P4 system.windows.forms, P5 2.0.0.0, P6 425751ea, P7 14b3, P8 13e, P9 system.componentmodel.win32, P10 NIL.

Data:
0000: 63 00 6c 00 72 00 32 00   c.l.r.2.
0008: 30 00 72 00 33 00 2c 00   0.r.3.,.
0010: 20 00 61 00 61 00 6c 00    .a.a.l.
0018: 69 00 73 00 74 00 65 00   i.s.t.e.
0020: 72 00 2e 00 65 00 78 00   r...e.x.
0028: 65 00 2c 00 20 00 31 00   e.,. .1.
0030: 2e 00 30 00 2e 00 30 00   ..0...0.
0038: 2e 00 30 00 2c 00 20 00   ..0.,. .
0040: 34 00 32 00 64 00 37 00   4.2.d.7.
0048: 66 00 39 00 65 00 32 00   f.9.e.2.
0050: 2c 00 20 00 73 00 79 00   ,. .s.y.
0058: 73 00 74 00 65 00 6d 00   s.t.e.m.
0060: 2e 00 77 00 69 00 6e 00   ..w.i.n.
0068: 64 00 6f 00 77 00 73 00   d.o.w.s.
0070: 2e 00 66 00 6f 00 72 00   ..f.o.r.
0078: 6d 00 73 00 2c 00 20 00   m.s.,. .
0080: 32 00 2e 00 30 00 2e 00   2...0...
0088: 30 00 2e 00 30 00 2c 00   0...0.,.
0090: 20 00 34 00 32 00 35 00    .4.2.5.
0098: 37 00 35 00 31 00 65 00   7.5.1.e.
00a0: 61 00 2c 00 20 00 31 00   a.,. .1.
00a8: 34 00 62 00 33 00 2c 00   4.b.3.,.
00b0: 20 00 31 00 33 00 65 00    .1.3.e.
00b8: 2c 00 20 00 73 00 79 00   ,. .s.y.
00c0: 73 00 74 00 65 00 6d 00   s.t.e.m.
00c8: 2e 00 63 00 6f 00 6d 00   ..c.o.m.
00d0: 70 00 6f 00 6e 00 65 00   p.o.n.e.
00d8: 6e 00 74 00 6d 00 6f 00   n.t.m.o.
00e0: 64 00 65 00 6c 00 2e 00   d.e.l...
00e8: 77 00 69 00 6e 00 33 00   w.i.n.3.
00f0: 32 00 20 00 4e 00 49 00   2. .N.I.
00f8: 4c 00 0d 00 0a 00         L..... 

references;
system.dll
system.data.dll
system.drawing.dll
system.windows.forms.dll
system.xml.dll

Thanks!