[Zope] IOError: [Errno 9] Bad file descriptor

[Erik Myllymaki]

I have an external method that uses reportlab to make

The method takes one argument, a Databse key, does a lookup of the 
database record for that key and then makes a PDF file using reportlab 
and writes it to the local HD of the zope server.

The method works well outside of Zope, but called from Zope, it only 
works every second time (exactly). The first call will work, but the 
second will fail with:

Error Type: IOError
Error Value: [Errno 9] Bad file descriptor

then the third call work work, etc. - any ideas?

- Zope 2.7.0 on windows 2000 Server.