Games : How do I fix my minecraft launcher when it keeps saying weird things?

I did what someone told me, to take out the string that has the incremental CMS in the advanced Java settings. Now its starting to say this:

[00:51:16] [Client thread/INFO]: Setting user: kassidygallowway
[00:51:16] [Client thread/INFO]: (Session ID is token:c4d1b961d86f4e4594f36a7ebaaa8901:ce288cc1399b4266a07c19cc48d47531)
Exception in thread "Client thread" com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was STRING at line 1 column 1
    at com.google.gson.Gson.fromJson(Gson.java:815)
    at com.google.gson.Gson.fromJson(Gson.java:768)
    at lu.b(SourceFile:151)
    at lu.<init>(SourceFile:43)
    at net.minecraft.server.MinecraftServer.<init>(SourceFile:155)
    at bpp.<init>(SourceFile:41)
    at avf.<init>(SourceFile:293)
    at net.minecraft.client.main.Main.main(SourceFile:124)
Caused by: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was STRING at line 1 column 1
    at com.google.gson.stream.JsonReader.beginArray(JsonReader.java:338)
    at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:79)
    at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:60)
    at com.google.gson.Gson.fromJson(Gson.java:803)
    ... 7 more

So can someone help me with this? I need to get on Minecraft, or I will miss my contest deadline. Please help.