[Konstantinos]

Use ' ' around %s placeholder.

pawn Код:

format(query, sizeof(query), "UPDATE playerdata SET Level=%d, Money=%d, IP='%s', Admin=%d, Skin=%d, Armour=%f, Health=%f, \
ConnectTime=%d, PosX=%f, PosY=%f, PosZ=%f, PosA=%f, VirtualWorld=%d, Interior=%d WHERE Username = '%s'",

EDIT: You should've posted in Scripting Help section.