Checked the accounts list and even attempted to manually create them in the UI. No luck
What I find bizarre is that it'll work fine if I haven't got the shop list in, but as soon as I "Load" the shop list. BAM. Same error. I'd nearly chalk it up as a data error as well due to a delimiting split but my list is clean of special characters besides the colon for the username:password separation.
Also just checked the buy list and it is also free of any special chars.
Have tried deleting and re-extracting the ZIP to no avail.
It works fine on a single account, but gets RS-banned pretty quickly unfortunately :\