That's the default texture & color when a texture isn't set (or is set but the file doesn't exist). Make sure you have an oUF_P3lim\media\minimalist.tga file. Also make sure you have these two lines in your oUF_P3lim.lua file:
Code:
local texture = [=[Interface\AddOns\oUF_P3lim\media\minimalist]=]
...
self.Health:SetStatusBarTexture(texture)