I've set up about 1000 Final Power Flower Bonsai Pot producing EMC.
However, after my EMC value reaches about 9.2E (9,223,372,036,854,776,000), I cannot insert any items into the transmutation table.
I can still pull items out of the transmutation table, and the EMC value still increases from the Power Flowers.
After I pulled out some items and reduced my EMC to a lower number, the problem was gone and I can insert items (until my EMC reaches about 9.22E again).
I can still insert items via the personal EMC link.

Just checked Project E's source and realized that the EMC value in a transmutation table is capped at the max value of long.

Well that sucks.