GD::OrgChart has some problems. I reviewed the readme to see what the dependencies are, and I noticed that it was designed with Perl module GD 1.41. The GD 1.x series had to drop support for GIF because of licensing issues. GIF support is back in the 2.x series; however, I don't think that GD::OrgChart supports it. It seems to be more suited for PNG, so give PNG a try instead of GIF.

If you really have to use GIF, there are a couple of things that need to be done. First, make sure you have GD in the 2.x series installed and that it has GIF support. You can check that using the command "gdlib-config --features"---it'll list the formats that it supports. Second, you might want to consider using Image::OrgChart instead of GD::OrgChart. Personally, I prefer Image::OrgChart.