http://bugs.winehq.org/show_bug.cgi?id=5967
------- Additional Comments From dank@kegel.com 2006-20-08 00:52 ------- The trial for version 5.21 works fine here with today's wine:
dank@lappy:~/.wine/drive_c/Keil/C166/bin$ ~/wine-git/wine l166.exe
L166 LINKER/LOCATER V5.21 - SN: Eval Version COPYRIGHT KEIL ELEKTRONIK GmbH 1991 - 2005
*** FATAL ERROR L201: INVALID COMMAND LINE SYNTAX POS: 1 L166.EXE # dank@lappy:~/.wine/drive_c/Keil/C166/bin$
So... maybe you just need to update?