This server will operate in LAN mode only.

[the Portaller]

I am getting this error on a Garry's Mod Dedicated Server:

Code:

[S_API_FAIL] SteamAPI_Init() failed; SteamAPI_IsSteamRunning() failed.
SteamGameServer_InitSafe failed!
************************************************** *********
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* Unable to load Steam support library. *
* Unable to load Steam support library. *
* This server will operate in LAN mode only. *
* This server will operate in LAN mode only. *
************************************************** *********
************************************************** *********

My IP is static, and ports 27000 - 27020 and 26901 TCP/UDP are open.

Server OS: Debian Jessie (testing)
Processor: Intel Celeron
Ram: 1 GB
Game(s): Garry's Mod
Start Up Command: [directory]/srcds_run -game garrysmod +maxplayers 24 +gamemode finalfrontier +map finalfrontier_a10 +sv_kickerrornum 0 +sv_alltalk 1

Things I've Tried: Copying the cstrike folder to [srcds directory]/orangebox, putting a steam_appdata.txt in the SRCDS directory, and updating and verifying the GMod server. How do I fix this problem?