@echo off
RustDedicated.exe -batchmode ^
+server.port 28015 ^
+server.level "CraggysIsland" ^
+server.seed 1 ^
+server.worldsize 1024 ^
+server.maxplayers 101 ^
+server.hostname "[rustyroll.com]events server ^
+server.identity "Identity" ^
+rcon.ip 127.0.0.1 ^
+rcon.port 28016 ^
+rcon.password rustyroll98 ^
+server.url "http://rustyroll.com" ^
+server.description "rustyroll's events server." ^
+server.ip 0.0.0.0 ^
-load ^
-silentcrash

server.level CraggyIsland

RustDedicated.exe -batchmode ^
+server.port 28015 ^
+server.level "CraggyIsland" ^
+server.maxplayers 50 ^
+server.hostname "[rustyroll.com]event server" ^
+server.identity "identity" ^
+rcon.ip 127.0.0.1 ^
+rcon.port 28016 ^
+rcon.password rustyr0ll44 ^
+query_port 28016 ^
+nav_disable true ^
-nologs ^
-load

I don't think that error on your client has to do with the level. I use CraggyIsland every time I start my test server.

Can I have your batch file please?

My .bat would be the same as the example .bat, with the exception of the level name change I mentioned previously.