We’ve just deployed a new dataserver patch, which should make certain inventory operations more reliable — this is intended to be an interim fix for problems when you buy something inworld (either directly or from a vendor) and the item doesn’t appear in your inventory. This patch is server-side and doesn’t require you to download a new version of Second Life.
This fix may also help with a known issue where inventory transfers fail in regions with poor performance (low time dilation and Sim FPS). Our developers are looking into the root cause for a longer-term solution; things should be better in the meantime.
(Note that this isn’t related to the previous announcement of group IMs not working, which has to do with the userserver).