Thanks for the reply, I am using OpenACS4.6.3 with PostgreSQL 7.3.2, I had tried 7.2 before but it also doesn't work. Is there something wrong with my installation process? At the very first time, I tried to install the package "dotlrn" alone, and the system inormed me about the dependencies which requires me to install other packages, I choose all required packages. But the process stop due to similar problems above. Then I discovered that the dependencies info in dotlrn.info doesn't contain some dotlrn packages such as "dotlrn-calendar", "dotlrn-bm". I tried to remove the unsucessful installation of dotlrn, but failed, so I installed openACS again. and this time in installing dotLRN, I clicked on every packages that come with the dotlrn downloads. And the above error was what I got.
