Build fails because of JARs in Netbeans web project (JSP)
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I have a really weird problem, when I try to build my jsp web project in Netbeans (with JDK7).

It says that absolutely all of my jars aren't readable (e.g. "error: error reading ...\lib\gson-1.5.jar; cannot read zip file") and so the build fails, but I don't think that my jars are corrupt.

At the end there is also 

"...\build-impl.xml:550: The following error occurred while executing this line: <br/>
...\build-impl.xml:263: Compile failed; see the compiler error output for details."

line 263 references to  
`<javac debug="@{debug}" deprecation="${javac.deprecation}" destdir="@{destdir}" encoding="${source.encoding}" excludes="@{excludes}" fork="${javac.fork}" includeantruntime="false" includes="@{includes}" source="${javac.source}" srcdir="@{srcdir}" target="${javac.target}">`  
in build-impl.xml


Any suggestions what the problem might be?
