BackupSoftFile::WriteMediaFileMark: failure on backup devic

I'm using SqlBackup (SQL Backup 4.2.0.511) (with MAXTRANSFERSIZE = 262144 setting), to logship data from my w2k sql2k to a second machine running the same version. The full backup always work, but the all subsequent tran backups fail with this errormessage.

Event Type: Error
Event Source: MSSQLSERVER
Event Category: (2)
Event ID: 17055
Date: 21/05/2006
Time: 21:00:13
User: ..\sqlserveragentUser
Computer: ..
Description:
18210 :
BackupSoftFile::WriteMediaFileMark: failure on backup device 'SQLBACKUP_07800ABD-35E9-44E6-BFE2-36FB7C5C821C'. Operating system error 995(The I/O operation has been aborted because of either a thread exit or an application request.).

Data:
0000: 22 47 00 00 10 00 00 00 "G......
0008: 0c 00 00 00 50 00 41 00 ....P.A.
0010: 52 00 4b 00 4d 00 4f 00 R.K.M.O.
0018: 42 00 49 00 4c 00 45 00 B.I.L.E.
0020: 31 00 00 00 00 00 00 00 1.......

tia
hjm