You already gave the culprit : php 5.6.25
As you are using v1.0.1 that is even older . V1.0.4 (latest of that line) runs nicely up to php version 5.3.
So you are facing 2 things : a php version that is too new for your version AND the version in use is old (should have been upgraded few years back).
Best solution was to ask host if you are able to run php 5.3 max. ( it is also related to mysql).
If this is not possible you will have to (local on pc) (keeping the backups stored!!) to update to v1.0.4.
Since that version also does not realy wants to run on php 5.6 than maybe v2.. Again local update from v1.0.1 to 1.0.4 to v2 (do not use the fresh github files, but a between v2 version).Keep checking if it all wants to run and if still fine> ultimately go to the latest files...
Keep us informed, if some extra info is needed...