Both. If the MoD actually paid for the trials and the proper programming of JPA, the Armed Forces would not see the debacle that has been suffered by all 3 services.
Leadership - by not sticking to their guns and fighting for the extra resources to make it right. For failing to educate people properly of the good and not so good points of JPA so everyone knows how to use it.
Admin - for not preparing properly for the conversion, for not meeting the KPIs set out to delivering JPA complaints and issues and finally for not ensuring the system was good to go prior to making this sorry episode come to life.
Really - it comes down to money and the desire to ensure that the correct product is put out on the streets with full confidence that it will work (with an acceptable amount of unforseen glitches - not a raft of them).