You can also open the character file and copy individual macros, rather than the whole character file. Use Notepad or Emerald Crimson Editor or other non-formatting editor to open it, NOT MS Word.
In Windows 7, the character file is found under Documents > EA Games > Ultima Online Stygian Abyss > User Data > Account Name > Shard > Character Name
Open that file and the macros are found in the section that starts with <Macros> and ends with </Macros>. Each line that starts with "<UserAction " and ends with "</UserAction>" is a macro. The "name=" is the name that you gave the macro when it was created.
By the way, you can repeat actions when you create a macro up to ten times, but you can copy and paste in this file to make the macro as long a you want.