Master Planning - Planned transfer order Number sequence 0 does not exist error in AX7

It looks like you don't have complete setup:

1) Check whether under Site settings check-box "Use transfer journals for movements within site" is ticked

2) Check whether under Inventory management parameters default Transfer journal is filled in.

Depending from your needs - both fields should be blank (to use transfer orders) of both fields should be filled (to use transfer journals instead of transfer orders)