Error message I'm getting whenever I try to open Forge

by teabo
Description: [just running the program]
- EOFException | Open
- Code: Select all
Forge Version: 1.5.12-r${forge.revision}${forge.specialStatus} (mixed revisions detected; please update from the root directory)
Operating System: Mac OS X 10.7.5 x86_64
Java Version: 1.7.0_51 Oracle Corporation
main > Error loading Quest Data
java.io.EOFException: Unexpected end of ZLIB input stream
at java.util.zip.InflaterInputStream.fill(InflaterInputStream.java:240)
at java.util.zip.InflaterInputStream.read(InflaterInputStream.java:158)
at java.util.zip.GZIPInputStream.read(GZIPInputStream.java:116)
at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:283)
at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:325)
at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:177)
at java.io.InputStreamReader.read(InputStreamReader.java:184)
at java.io.Reader.read(Reader.java:140)
at forge.quest.io.QuestDataIO.loadData(QuestDataIO.java:127)
at forge.control.FControl.initialize(FControl.java:222)
at forge.view.Main.main(Main.java:42)