By default each profile is allowed to have 1 log 'source' associated with it. In order to accommodate the processing of historical logs, Urchin will process more than this number of log files. However, it is a licensing violation to exceed this number for regular daily processing and Urchin will issue the requisite warning message when this condition exists. An upgrade to the license can be purchased that will allow for more log files to be associated with each profile.
A log 'source' is a path to a single log or a set of logs that are all created on one web server for one web site. That means that while one profile can only have one log source, that source can point to 24 different logs in a single day in the case where the web server rotates the log every hour.