Android APP stopped working after new eclipse + sdk download

My APP was running perfectly. I moved it to a new Windows computer, installed eclipse + android sdk, and now I get the following error messages when I try to run it.

[2013-12-12 20:39:23 - Dex Loader] Unable to execute dex: Multiple dex files define Lorg/json/simple/ItemList;
[2013-12-12 20:39:23 - MyPulse] Conversion to Dalvik format failed: Unable to execute dex: Multiple dex files define Lorg/json/simple/ItemList;
[2013-12-12 22:17:58 - MyPulse] Dx
trouble writing output: already prepared
[2013-12-12 22:18:04 - Dex Loader] Unable to execute dex: Multiple dex files define Lorg/json/simple/ItemList;
[2013-12-12 22:18:04 - MyPulse] Conversion to Dalvik format failed: Unable to execute dex: Multiple dex files define Lorg/json/simple/ItemList;
[2013-12-12 22:40:08 - MyPulse] Dx
trouble writing output: already prepared
[2013-12-12 22:40:12 - Dex Loader] Unable to execute dex: Multiple dex files define Lorg/json/simple/ItemList;
[2013-12-12 22:40:12 - MyPulse] Conversion to Dalvik format failed: Unable to execute dex: Multiple dex files define Lorg/json/simple/ItemList;
[2013-12-12 22:42:47 - MyPulse] Dx
trouble writing output: already prepared
[2013-12-12 22:42:52 - Dex Loader] Unable to execute dex: Multiple dex files define Lorg/json/simple/ItemList;
[2013-12-12 22:42:52 - MyPulse] Conversion to Dalvik format failed: Unable to execute dex: Multiple dex files define Lorg/json/simple/ItemList;
[2013-12-12 23:25:28 - MyPulse] Dx
trouble writing output: already prepared
[2013-12-12 23:25:32 - Dex Loader] Unable to execute dex: Multiple dex files define Lorg/json/simple/ItemList;
[2013-12-12 23:25:32 - MyPulse] Conversion to Dalvik format failed: Unable to execute dex: Multiple dex files define Lorg/json/simple/ItemList;
[2013-12-12 23:25:46 - MyPulse] Dx
trouble writing output: already prepared
[2013-12-12 23:25:49 - Dex Loader] Unable to execute dex: Multiple dex files define Lorg/json/simple/ItemList;
[2013-12-12 23:25:49 - MyPulse] Conversion to Dalvik format failed: Unable to execute dex: Multiple dex files define Lorg/json/simple/ItemList;
[2013-12-12 23:37:20 - MyPulse] Dx
trouble writing output: already prepared
[2013-12-12 23:37:23 - Dex Loader] Unable to execute dex: Multiple dex files define Lorg/json/simple/ItemList;
[2013-12-12 23:37:23 - MyPulse] Conversion to Dalvik format failed: Unable to execute dex: Multiple dex files define Lorg/json/simple/ItemList;
[2013-12-12 23:37:30 - MyPulse] Dx
trouble writing output: already prepared
[2013-12-12 23:37:35 - Dex Loader] Unable to execute dex: Multiple dex files define Lorg/json/simple/ItemList;
[2013-12-12 23:37:35 - MyPulse] Conversion to Dalvik format failed: Unable to execute dex: Multiple dex files define Lorg/json/simple/ItemList;
[2013-12-12 23:38:15 - MyPulse] Dx
trouble writing output: already prepared
[2013-12-12 23:38:18 - Dex Loader] Unable to execute dex: Multiple dex files define Lorg/json/simple/ItemList;
[2013-12-12 23:38:18 - MyPulse] Conversion to Dalvik format failed: Unable to execute dex: Multiple dex files define Lorg/json/simple/ItemList;
[2013-12-12 23:38:40 - MyPulse] Dx
trouble writing output: already prepared
[2013-12-12 23:38:44 - Dex Loader] Unable to execute dex: Multiple dex files define Lorg/json/simple/ItemList;
[2013-12-12 23:38:44 - MyPulse] Conversion to Dalvik format failed: Unable to execute dex: Multiple dex files define Lorg/json/simple/ItemList;