Don't know if this is of anyone's interest but, in order to use this latest version I first tried with java7 (as I'm using it), and the launcher script failed (stack trace at the end), then I tried with java6, it downloaded correctly and initialized the project, then moved back to java7, and now its working (as I suppose the initialization was handled correctly by java6).
$ xsbt
Getting net.java.dev.jna jna 3.2.3 ...
:: retrieving :: org.scala-tools.sbt#boot-app
confs: [default]
1 artifacts copied, 0 already retrieved (838kB/63ms)
Getting Scala 2.9.1 (for sbt)...
:: retrieving :: org.scala-tools.sbt#boot-scala
confs: [default]
4 artifacts copied, 0 already retrieved (19939kB/516ms)
Getting org.scala-tools.sbt sbt_2.9.1 0.11.0 ...
java.lang.AbstractMethodError
at java.util.AbstractCollection.addAll(AbstractCollection.java:333)
at com.sun.org.apache.xerces.internal.util.ParserConfigurationSettings.addRecognizedFeatures(ParserConfigurationSettings.java:115)
at com.sun.org.apache.xerces.internal.impl.xs.opti.SchemaParsingConfig.addRecognizedParamsAndSetDefaults(SchemaParsingConfig.java:944)
at com.sun.org.apache.xerces.internal.impl.xs.opti.SchemaParsingConfig.<init>(SchemaParsingConfig.java:352)
at com.sun.org.apache.xerces.internal.impl.xs.opti.SchemaParsingConfig.<init>(SchemaParsingConfig.java:255)
at com.sun.org.apache.xerces.internal.impl.xs.traversers.XSDHandler.<init>(XSDHandler.java:464)
at com.sun.org.apache.xerces.internal.impl.xs.traversers.XSDHandler.<init>(XSDHandler.java:471)
at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaLoader.<init>(XMLSchemaLoader.java:344)
at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaLoader.<init>(XMLSchemaLoader.java:293)
at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.<init>(XMLSchemaValidator.java:1135)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.configurePipeline(XML11Configuration.java:1199)
at com.sun.org.apache.xerces.internal.parsers.XIncludeAwareParserConfiguration.configurePipeline(XIncludeAwareParserConfiguration.java:156)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:805)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:764)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:123)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1210)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:568)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl.parse(SAXParserImpl.java:302)
at org.apache.ivy.util.XMLHelper.parse(XMLHelper.java:131)
at org.apache.ivy.util.XMLHelper.parse(XMLHelper.java:84)
at org.apache.ivy.plugins.parser.xml.XmlModuleDescriptorParser$Parser.parse(XmlModuleDescriptorParser.java:248)
at org.apache.ivy.plugins.parser.xml.XmlModuleDescriptorParser.parseDescriptor(XmlModuleDescriptorParser.java:112)
at scala.collection.mutable.FlatHashTable$class.parseDescriptor(Proxy.scala:48)
at org.apache.ivy.core.cache.ModuleDescriptorProvider.provideModule$6172736d(DefaultRepositoryCacheManager.java:659)
at org.apache.ivy.core.cache.ModuleDescriptorMemoryCache.getStale(ModuleDescriptorMemoryCache.java:68)
at org.apache.ivy.core.cache.DefaultRepositoryCacheManager.cacheModuleDescriptor(DefaultRepositoryCacheManager.java:993)
at org.apache.ivy.plugins.resolver.BasicResolver.parse(BasicResolver.java:546)
at org.apache.ivy.plugins.resolver.BasicResolver.getDependency(BasicResolver.java:266)
at org.apache.ivy.plugins.resolver.ChainResolver.getDependency(ChainResolver.java:104)
at org.apache.ivy.core.resolve.IvyNode.loadData(IvyNode.java:169)
at org.apache.ivy.core.resolve.VisitNode.loadData(VisitNode.java:287)
at org.apache.ivy.core.resolve.ResolveEngine.fetchDependencies(ResolveEngine.java:696)
at org.apache.ivy.core.resolve.ResolveEngine.doFetchDependencies(ResolveEngine.java:781)
at org.apache.ivy.core.resolve.ResolveEngine.fetchDependencies(ResolveEngine.java:704)
at org.apache.ivy.core.resolve.ResolveEngine.doFetchDependencies(ResolveEngine.java:781)
at org.apache.ivy.core.resolve.ResolveEngine.fetchDependencies(ResolveEngine.java:704)
at org.apache.ivy.core.resolve.ResolveEngine.doFetchDependencies(ResolveEngine.java:781)
at org.apache.ivy.core.resolve.ResolveEngine.fetchDependencies(ResolveEngine.java:704)
at org.apache.ivy.core.resolve.ResolveEngine.doFetchDependencies(ResolveEngine.java:781)
at org.apache.ivy.core.resolve.ResolveEngine.fetchDependencies(ResolveEngine.java:704)
at org.apache.ivy.core.resolve.ResolveEngine.doFetchDependencies(ResolveEngine.java:781)
at org.apache.ivy.core.resolve.ResolveEngine.fetchDependencies(ResolveEngine.java:704)
at org.apache.ivy.core.resolve.ResolveEngine.getDependencies(ResolveEngine.java:576)
at org.apache.ivy.core.resolve.ResolveEngine.resolve(ResolveEngine.java:237)
at xsbt.boot.Update.xsbt$boot$Update$$lockedApply(JavaConversions.scala:84)
at xsbt.boot.Update$$anon$3.call(Update.scala:78)
at xsbt.boot.Locks$GlobalLock.withChannel$1(Locks.scala:75)
at xsbt.boot.Locks$GlobalLock.withChannelRetries$1(Locks.scala:58)
at xsbt.boot.Locks$GlobalLock$$anonfun$withFileLock$1.apply(Locks.scala:79)
at xsbt.boot.Using$.withResource(Using.scala:11)
at xsbt.boot.Using$.apply(Using.scala:10)
at xsbt.boot.Locks$GlobalLock.liftedTree1$1(Locks.scala:51)
at xsbt.boot.Locks$GlobalLock.withLock(Locks.scala:51)
at xsbt.boot.Locks$.apply0(Locks.scala:30)
at xsbt.boot.Locks$.apply(Locks.scala:27)
at xsbt.boot.Update.apply(JavaConversions.scala:79)
at xsbt.boot.Provider$initialize.call(Provider.scala:34)
at xsbt.boot.Locks$GlobalLock.withChannel$1(Locks.scala:75)
at xsbt.boot.Locks$GlobalLock.withChannelRetries$1(Locks.scala:58)
at xsbt.boot.Locks$GlobalLock$$anonfun$withFileLock$1.apply(Locks.scala:79)
at xsbt.boot.Using$.withResource(Using.scala:11)
at xsbt.boot.Using$.apply(Using.scala:10)
at xsbt.boot.Locks$GlobalLock.liftedTree1$1(Locks.scala:51)
at xsbt.boot.Locks$GlobalLock.withLock(Locks.scala:51)
at xsbt.boot.Locks$.apply0(Locks.scala:30)
at xsbt.boot.Locks$.apply(Locks.scala:27)
at scala.collection.mutable.FlatHashTable$class.$init$(Proxy.scala:32)
at xsbt.boot.Launch$ScalaProvider$AppProvider.<init>(Launch.scala:128)
at xsbt.boot.Launch$ScalaProvider.app(Launch.scala:126)
at xsbt.boot.Launch$.run(Launch.scala:50)
at xsbt.boot.Launch$$anonfun$explicit$1.apply(Launch.scala:43)
at xsbt.boot.Launch$.launch(Launch.scala:68)
at xsbt.boot.Launch$.apply(Launch.scala:14)
at xsbt.boot.Boot$.runImpl(Boot.scala:24)
at xsbt.boot.Boot$.main(Boot.scala:15)
at xsbt.boot.Boot.main(Boot.scala)
Error during sbt execution: java.lang.AbstractMethodError
Cheers