Fast workaround:

*** sogo-dist/chrome/content/sogo-connector/addressbook/categories.js 2013-04-17 16:54:08.000000000 +0400
--- sogo/chrome/content/sogo-connector/addressbook/categories.js 2013-09-18 15:16:57.971057887 +0400

* 6,11 **
--- 6,12 ----
.getService(Components.interfaces.nsIPrefBranch);
try {
cats = prefService.getCharPref("sogo-connector.contacts.categories");

• cats = decodeURIComponent(escape(cats));
  }
  catch(e) {
  let strService = Components.classes["@mozilla.org/intl/stringbundle;1"]

  ---

  * 20,26 **
  setCategoriesAsString: function SCCC_setCategoriesAsString(cats) {
  let prefService = Components.classes["@mozilla.org/preferences-service;1"]
  .getService(Components.interfaces.nsIPrefBranch);
  ! prefService.setCharPref("sogo-connector.contacts.categories", cats);
  },

  getCategoriesAsArray: function SCCC_getCategoriesAsArray() {
  --- 21,27 ----
  setCategoriesAsString: function SCCC_setCategoriesAsString(cats) {
  let prefService = Components.classes["@mozilla.org/preferences-service;1"]
  .getService(Components.interfaces.nsIPrefBranch);
  ! prefService.setCharPref("sogo-connector.contacts.categories", unescape(encodeURIComponent(cats)));
  },

  getCategoriesAsArray: function SCCC_getCategoriesAsArray() {

I don't think it's a fast-workaround but a rather clean fix. Has it been working ok for you?

Yes, it's working for me.

Please submit 2 pull requests on github.com fro sogo-connector tb17 and tb24.

Any updates on this?

https://github.com/inverse-inc/sogo-connector.tb24/commit/6c8ee8bcc26faeb874e15fe152ef0cb91406fd66