habe in einem tiger skin album seit gestern diese fehlermeldung, was kann das problem sein?

Stack trace for jAlbum 37.0.2 using skin Tiger 6.4.1:

se.datadosen.util.ScriptException: C:\Users\anmuht\AppData\Roaming\JAlbum\skins\Tiger\lib\util.js:5687 ReferenceError: "ex" is not defined in common.css at line number 1
at se.datadosen.util.ScriptException.of(ScriptException.java:59)
at se.datadosen.jalbum.ast.ScriptletNode.doEval(ScriptletNode.java:99)
at se.datadosen.jalbum.ast.ASTNode.eval(ASTNode.java:50)
at se.datadosen.jalbum.ast.GroupNode.doEval(GroupNode.java:78)
at se.datadosen.jalbum.ast.ASTNode.eval(ASTNode.java:50)
at se.datadosen.jalbum.AST.eval(AST.java:68)
at se.datadosen.jalbum.AlbumBean.processTemplateFile(AlbumBean.java:1607)
at se.datadosen.jalbum.AlbumBean.makeAlbumForFolder(AlbumBean.java:1845)
at se.datadosen.jalbum.AlbumBean.makeAlbum(AlbumBean.java:3712)
at se.datadosen.jalbum.AlbumBean.smartMakeAlbum(AlbumBean.java:3549)
at se.datadosen.jalbum.JAlbumFrame$7.run(JAlbumFrame.java:1196)
Caused by: javax.script.ScriptException: ReferenceError: "ex" is not defined in C:\Users\anmuht\AppData\Roaming\JAlbum\skins\Tiger\lib\util.js at line number 5687
at org.openjdk.nashorn.api.scripting.NashornScriptEngine.throwAsScriptException(NashornScriptEngine.java:436)
at org.openjdk.nashorn.api.scripting.NashornScriptEngine.evalImpl(NashornScriptEngine.java:420)
at org.openjdk.nashorn.api.scripting.NashornScriptEngine$1.eval(NashornScriptEngine.java:476)
at java.scripting/javax.script.CompiledScript.eval(Unknown Source)
at se.datadosen.jalbum.ast.ScriptletNode.doEval(ScriptletNode.java:67)
... 9 more
Caused by: C:\Users\anmuht\AppData\Roaming\JAlbum\skins\Tiger\lib\util.js:5687 ReferenceError: "ex" is not defined
at org.openjdk.nashorn.internal.runtime.ECMAErrors.error(ECMAErrors.java:57)
at org.openjdk.nashorn.internal.runtime.ECMAErrors.referenceError(ECMAErrors.java:318)
at org.openjdk.nashorn.internal.runtime.ECMAErrors.referenceError(ECMAErrors.java:290)
at org.openjdk.nashorn.internal.objects.Global.__noSuchProperty__(Global.java:1604)
at org.openjdk.nashorn.internal.scripts.Script$Recompilation$110$144901AZA$util.deleteFolder(C:\Users\anmuht\AppData\Roaming\JAlbum\skins\Tiger\lib\util.js:5687)
at org.openjdk.nashorn.internal.scripts.Script$Recompilation$106$146231A$util.syncGoogleFonts(C:\Users\anmuht\AppData\Roaming\JAlbum\skins\Tiger\lib\util.js:5729)
at org.openjdk.nashorn.internal.scripts.Script$87$\^eval\_.:program(<eval>:128)
at org.openjdk.nashorn.internal.runtime.ScriptFunctionData.invoke(ScriptFunctionData.java:646)
at org.openjdk.nashorn.internal.runtime.ScriptFunction.invoke(ScriptFunction.java:506)
at org.openjdk.nashorn.internal.runtime.ScriptRuntime.apply(ScriptRuntime.java:519)
at org.openjdk.nashorn.api.scripting.NashornScriptEngine.evalImpl(NashornScriptEngine.java:415)
... 12 more