Unable to enable unpacking for maven assembly plugin

I'm using maven-assembly-plugin to assemble a module in a multi-module maven project.

I get an error:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-assembly-plugin:2.2-beta-5:single (jar-with-dependencies) on project socialweb-importer: 
Failed to create assembly: Error adding file-set for 'com.almworks.sqlite4java:libsqlite4java-linux-i386:so:1.0.392' to archive: Error adding archived file-set. PlexusIoResourceCollection not found for: /home/user/.m2/repository/com/almworks/sqlite4java/libsqlite4java-linux-i386/1.0.392/libsqlite4java-linux-i386-1.0.392.so: 
No such archiver: 'so'. -> [Help 1]

I added assembly.xml file to enable a custom assembly and disable the unpacking for the .so file but that didn't work either.

My assembly file looks like this:

<assembly xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.3"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.3 http://maven.apache.org/xsd/assembly-1.1.3.xsd">
    <id>jar-with-dependencies</id>
    <formats>
        <format>jar</format>
    </formats>
    <includeBaseDirectory>false</includeBaseDirectory>
    <dependencySets>
        <dependencySet>
            <outputDirectory>/</outputDirectory>
            <useProjectArtifact>true</useProjectArtifact>
            <unpack>true</unpack>
            <scope>runtime</scope>
        </dependencySet>
    </dependencySets>
</assembly>

And my POM file includes the configuration of plugin like this:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-assembly-plugin</artifactId>
    <executions>
        <execution>
            <id>jar-with-dependencies</id>
            <phase>prepare-package</phase>
            <goals>
                <goal>single</goal>
            </goals>
            <configuration>
                <descriptor>src/assembly/assembly.xml</descriptor>
                <appendAssemblyId>false</appendAssemblyId>
            </configuration>
        </execution>
    </executions>
</plugin>

What exactly am I doing wrong?