Cannot create Window

[Administration]

I am having trouble creating windows in SunView.  I keep getting the
message

no more windows available
WIN ioctl number 1c: No such file or directory
couldn't get a new subwindow
cmdtool - /bin/csh: No such file or directory
window: Subwindow creation failed.
window: Subwindow creation failed.
No such file or directory

or a variant thereof.  The implication is that I have too many windows
open and have simply run out of windows.  The problem is that I don't have
that many windows open.  In fact, I usually have many more widows open,
and have never before run into this problem.  It seems to me that the
system has probably failed to clear an internal list somewhere, and
therefore is under the misapprehension that there are allocated windows
that are not actually in use.  I suspect that I could probably make the
problem go away by rebooting the system, but I would rather not resort to
such drastic measures.  Does anybody know how I can fix this situation
without rebooting?  Thanks in advance for any help.  

Scott Smith
adm at apollo.drexel.edu