I am running aMule 2.1.3 in Edubuntu 7.04. In Preferences->Security->Default Permissions, the defaults of a new installation of aMule are 640 for files and 750 for directories. I think you should set it to be 644 for files and 755 for directories by default, which is the standard for one's regular files. Otherwise one will have problems sharing those files with others.