Using Eyad Ebrahim's suggestions, I was able to examine the IvyDE console and gain insight into the problem. The issue turned out to be that several developers did not have an ivysettings.xml set in either the eclipse global or project IvyDE properties. IvyDE was attempting to use an internet resolver by default, which resulted in two subsequent issues including no public repo for products like worldwind, and blocking of certain files by my company network infrastructure. After correctly configuring the ivysettings.xml file, the custom file/url resolvers listed above were used and everything worked.
Thanks!