We also had a problem with inotes and the Quickr plugin. Some users where able to use the plugin other not.
Sympthom:
When trying to add places using the inotes interface, no list is displayed when entering the quickr URL for some users. Others users does see a list of places when entering the quickr URL.
Cause:
After some debugging it seems that the problem occurs when with places with certain characters in the description field. e.g & or / (maybe there are more). The XML parser can not handle the characters in the description fields, while it can handle special characters in the title field. Users which are member of places with these characters in the description field will have problems to add places.
Interim solution:
Remove special characters form the description fields of the quickr places
Personally I think this is a bug, so we have created a PMR for this.