I got a repeatable error using TCC 10.00.38 Windows XP [Version 5.1.2600] (with SP3) This did not happen in TCC 9 and earlier (and it was the first time I tried it in v 10). It TCC 8 and 9, it worked as expected. C:\work> dir tv_watch.tws Volume in drive C is IRVING-C Serial number is 28aa:b2d9 Directory of C:\work\tv_watch.tws 01-19-2009 22:59 1,145 tv_watch.tws 1,145 bytes in 1 file and 0 dirs 4,096 bytes allocated 12,870,094,848 bytes free C:\work> assoc .tws .tws=TextPad.tws C:\work> ftype TextPad.tws TextPad.tws="C:\Program Files\TextPad 4\TextPad.exe" -s C:\work> tv_watch.tws TCC: (Sys) The system cannot find the path specified. "" (%?=2, %_?=2) C:\work> "C:\Program Files\TextPad 4\TextPad.exe" -s tv_watch.tws (It worked.) (The line with %? and %_? is a result of my PROMPT variable, and is self-explanatory. The source is SET PROMPT=`%@if[%?%_? eq 0,,$c%%%%?$q$r,$s%%%%_?$q%_?$f$_]$P$g$s` (all on one line, of course).