the following steps reproduce this problem.  in summary, when adding two files whose names differ only by a dash and underscore, e.g. a-1.txt and a_1.txt, only the file with the dash in its name will be added, even though fossil add reports that both were added.  this test was conducted using powershell on windows 7 64 bit.  i can test it on windows xp later this week.  i don't have a non-windows box to test this on.

<pre>
PS C:\rev\src> fossil new test.fossil
project-id: 9968296e3e87d77b514493152ecc682e94e015cc
server-id:  37ea13bc92c88ff92f41f5ec8c921a88eeca87a8
admin-user: rev (initial password is "4cabdf")
PS C:\rev\src> md test
PS C:\rev\src> cd test
PS C:\rev\src\test> fossil open ..\test.fossil
PS C:\rev\src\test> echo "hello" > a_1.txt
PS C:\rev\src\test> echo "goodbye" > a-1.txt
PS C:\rev\src\test> ls

    Directory: C:\rev\src\test

Mode                LastWriteTime     Length Name
----                -------------     ------ ----
-a---         2/28/2010   6:23 PM         20 a-1.txt
-a---         2/28/2010   6:22 PM         16 a_1.txt
-a---         2/28/2010   6:22 PM       7168 _FOSSIL_

PS C:\rev\src\test> fossil add *.txt
ADDED  a-1.txt
ADDED  a_1.txt
PS C:\rev\src\test> fossil extras
a_1.txt
PS C:\rev\src\test> fossil ls
a-1.txt
PS C:\rev\src\test> fossil commit -m "underscore omitted"
New_Version: e6cb6574e973b8743701ec4e8f7cfaa61066c99a
PS C:\rev\src\test> fossil extras
a_1.txt
PS C:\rev\src\test> fossil ls
a-1.txt
PS C:\rev\src\test>
</pre>

fossil add can't add two files whose names only differ by an underscore or dash