It could be one of two things.
1. Check in your library manager under Built in libraries that the custom component library is loaded. It should be as it's part of the default ArchiCAD package, but just check to make sure it's ok. If you have the special menu activated it is possable to turn it off, but because there are two of you that have the same problem, I doubt that both of you have done that.
2. Check in the add-ons manager that the Custom component add- on is active. Again, it should be as it is part of the standard package.
What version of AC 11 are you using INT or US? I'm not familiar with the US library structure, but make sure that your Individual macro objects are in the active library as well, if they are not part of an LCF. Have you downloaded any libray updates recently? If you have, just check to make sure every thing is there.
HTH.
Ben