Clearcase needs to use UNC paths for the view storage directory, if you don't use it, you get the following error.

2010-02-19 23:58:55,149 WARN  [InitialPinger1] fisheye.app com.atlassian.fisheye.clearcase.ClearCaseContext-handleProcessError - 
Error executing command (cleartool mkview -snapshot -tag fisheye -vws d:\path\toviews\fisheye.vws d:\path\toviews\fisheye.vws ) : 
Non-zero exit code: 1 cleartool: Error: storage directory must be in UNC style (e.g. \\host\share\...)

• http://www.ipnom.com/ClearCase-Commands/mkview.html

  -vws
  Specifies the location for the snapshot view storage directory. On Windows systems, this must be a UNC name.
  For information on using this option to create snapshot views for disconnected use, see the section, "Disconnected Use of Snapshot Views".
  We recommend that you use -stgloc rather than this option whenever possible.

We should probably validate the input better.