[Cartoweb-users] Failed writing image Cartoweb 3.0

[WF morrison]

Hi,
I am still working on getting the demo running. I get the following errors:

Warning: [MapServer Error]: msSaveImageGD(): Unable to open file
/usr/local/cartoweb3/www-data/icons/demo/demo/agglo_class_0.png for
writing in /usr/local/cartoweb3/coreplugins/layers/server/LayersInitProvider.php
on line 206
Fatal error: Failed writing image to
/usr/local/cartoweb3/www-data/icons/demo/demo/agglo_class_0.png in
/usr/local/cartoweb3/coreplugins/layers/server/LayersInitProvider.php
on line 206

It appears to me that the permissions for icons/demo/demo are set
correctly.  What should I check next?
Thanks in advance,
Bill