Problems with shell command (Windows 2008 Server)

[Ben Rubinstein]

Has anyone encountered problems with the shell command not returning, on 
Windows 2008 Server?

I've got an app written in LC, which does a bunch of jobs configured by a 
script file (not a file of LiveCode syntax, just a set of instructions in an 
XML syntax); finishing with a bunch of batch files which the LC app invokes 
shell to do.

The app is scheduled to run unattended every night on a faceless VM in a rack 
somewhere.  It sends email when the whole job finishes sucessfully, or earlier 
than that if one of the tasks encounters a problem.

Emails are currently only coming through perhaps one run in three.  It appears 
to be hanging during one of these final batch files - not always the same one; 
and as far as one can tell from circumstantial evidence, the batch file itself 
seems to have completed, but the shell command hasn't returned.

The core of this app is in use lots of place for years; the shell feature is 
used less often.  Have other people encountered it appearing to hang 
intermittently in this way?

TIA,

Ben