[Zope] Mystery error: "The resource you requested is temporarily unavailable"

[Milos Prudek]

Chris McDonough wrote:
> Are you sure Zope isn't dying on that particular request and
> restarting itself?

No, I'm not sure.

Is there a way to find out more precisely the error cause, other than 
selectively commenting out parts of my source code?

Could it be caused by an External method quoted below?

***
def filetype(File=''):
    import os
    cmd='file -b -'
    w,r=os.popen2(cmd)
    w.write(File)
    w.close()
    return r.read().strip()
***

Thanks for any hints.

-- 
Milos Prudek