I recently have been having trouble placing Ads on Perth Gumtree, it seems that the AdBlock Plus Subscription was causing blocking of the placement of a new ad. Disabling the plugin allowed Ads to be placed however it was not the best method of dealing with it.
I decided to track the problem down using AdBlock Plus Diagnostics which proved useful.
Problem: Placing a Ad on Gumtree was not working on Firefox while AdBlock Plus was enabled.
Installed AdBlock Plus Diagnostics to see what was being blocked.
Edited my AdBlock Plus subscription to disable kijiji from being blocked.
Placing a advert on Gumtree now works!