savelines() unable to create files

[Yen]

I had a script logging things such as item trades.
The file it saved to didn't exist, but I thought it would create it; it didn't.
If this isn't intended, could it be fixed?

I planned on having it make a log file for each player, so situations can be dealt with without having to search through a huge text file; as it is, I have to rename it every 3 days because it exceeds 2000 lines.