It's a very strange crash, it is definitely gamedata-shaped but the stack doesn't make a lot of sense (but that is common with this sort of issue).
Could you see what you have in `addons\sourcemod\gamedata\tf2.items.txt`? And make sure you've got 1.6.4-279 installed from
https://builds.limetech.io/?p=tf2items
The gamedata in the download should have 479 as the linux offset, which should then be auto-updated by SourceMod to 488 on first server start.
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