I made some manual edits to my backup configuration file in notepad (all I changed was my hail message andmusic setting) and when I typed /load backup.cfg the game terminated.

From the Error log:

Windows 5.01.2600 (platform 2) Service Pack 1
ExceptionCode: 0xc0000005 Access Violation
ExceptionFlags: 0x00000000
ExceptionRecord: 0x00000000
ExceptionAddress: 0x0042E25D
NumberParameters: 2
0x00000000
0x00000030

ContextFlags: 0x0001003f
EFlags: 0x00010202
ds 0x00000023 35
es 0x00000023 35
fs 0x00000038 56
gs 0x00000000 0
cs 0x0000001b 27
ss 0x00000023 35
eax 0x00000004 4
ecx 0x02b0a4c0 45130944
edx 0x02b07138 45117752
ebx 0x02b07128 45117736
esi 0x0055c580 5621120
edi 0x02b0a4c0 45130944
ebp 0x0012cfd8 1232856
eip 0x0042e25d 4383325
esp 0x0012cfd8 1232856
brk> 0042e25d: 02b0a4c0 0055c580 02b07128 00ee12d8
- 0042eea9: 02b0a4c0 0055c580 00ee12d8 00000001
- 00439d4a: 00ee12d8 02b07128 05010099 00ee12d8
- 004430f7: 00000120 02b07128 024fc330 00ee12d8
- 00445d71: 00ee12d8 00ee12d8 0012d0ac 004448f2
- 0044321d: 00ee12d8 02b070c8 00000000 0012d0c8
- 004448f2: 024fc330 02b07038 02adbd98 00ee12d8
- 00444aa3: 00ee12d8 02b07038 02adbd98 02adbc18
- 0044567f: 00ee12d8 00ee12d8 0012d150 004414a6
- 0044321d: 00ee12d8 02b07028 00000001 0012d1ac
- 004414a6: 00ee12d8 0012d1f8 00000000 00000000
- 00442aea: 00ee12d8 00441490 0012d1f8 02b0a4c0
- 0044362c: 01ee12d8 00441490 0012d1f8 00000020
- 0044150a: 00ee12d8 00000004 00000001 00000001
- 00438ec1: 00ee12d8 00000004 00000001 00ee12d8
- 0043cde6: 02b0a4c0 0000000d 02684460 43968ce9
- 0043772d: 0000000d 0012d36c 0041891f 0000000d
- 00407538: 0000000d 0012dc8c 00000000 0012d3e0
- 0041891f: 000b029e 00000102 0000000d 001c0001
- 77d48654: 00418620 000b029e 00000102 0000000d
- 77d48723: 00000000 00418620 000b029e 00000102
- 77d4a7eb: 00418620 000b029e 00000102 0000000d
- 77d4aa95: 00418620 000b029e 00000102 0000000d
- 66027ecf: 00418620 000b029e 00000102 0000000d
- 6660411d: 00418620 000b029e 00000102 0000000d
- 010071e2: 00000000 00000000 00000000 00000000

fixed for the new client.