This is the output I get when starting with the Aerostar-700 :

Loading local weather routines...
'/home/syd/FGFS/data'
Nasal runtime error: bad/missing argument to subvec()
  at /home/syd/FGFS/data/Nasal/string.nas, line 226
  called from: /home/syd/FGFS/data/Nasal/string.nas, line 236
  called from: /home/syd/FGFS/data/Nasal/string.nas, line 203
  called from: /home/syd/FGFS/data/Nasal/multiplayer.nas, line 378
  called from: /home/syd/FGFS/data/Nasal/multiplayer.nas, line 446
'/home/syd/FGFS/data'
Nasal runtime error: bad/missing argument to subvec()
  at /home/syd/FGFS/data/Nasal/string.nas, line 226
  called from: /home/syd/FGFS/data/Nasal/string.nas, line 236
  called from: /home/syd/FGFS/data/Nasal/string.nas, line 203
  called from: /home/syd/FGFS/data/Nasal/io.nas, line 210
Nasal runtime error: props.setAttribute() with invalid attribute
  at /home/syd/FGFS/data/Nasal/props.nas, line 25
  called from: /home/syd/FGFS/data/Nasal/gui.nas, line 137
'/home/syd/FGFS/data/Aircraft/Aerostar-700/Models/Liveries'
Nasal runtime error: bad/missing argument to subvec()
  at /home/syd/FGFS/data/Nasal/string.nas, line 226
  called from: /home/syd/FGFS/data/Nasal/string.nas, line 236
  called from: /home/syd/FGFS/data/Nasal/string.nas, line 203
  called from: /home/syd/FGFS/data/Nasal/gui.nas, line 376
  called from: /home/syd/FGFS/data/Nasal/aircraft.nas, line 519
  called from: /home/syd/FGFS/data/Aircraft/Aerostar-700/Nasal/systems.nas, line 6

the '/home/syd/FGFS/data' lines are debug output suggested by Melchior to check that the path string was being constructed properly.
I can run the cvs compiled binary with the git /fgdata without errors , though that version was last compiled about a month ago.
I compared the cvs and git /src/Scripting files and I see no changes there.