PyDev for Eclipse installation fails

I'm trying to install PyDev 4.5 on Eclipse 3.7. I'm running Ubuntu 12.04.

Unfortunately the installation fails with the following error message:

An error occurred while collecting items to be installed
session context was:(profile=PlatformProfile, phase=org.eclipse.equinox.internal.p2.engine.phases.Collect, operand=, action=).
Problems downloading artifact: osgi.bundle,com.python.pydev,4.5.4.201601292234.
Error reading signed content:/tmp/signatureFile317604218647133996.jar
An error occurred while processing the signatures for the file: /tmp/signatureFile317604218647133996.jar
Problems downloading artifact: osgi.bundle,com.python.pydev.analysis,4.5.4.201601292234.
Error reading signed content:/tmp/signatureFile1653935437183270228.jar
An error occurred while processing the signatures for the file: /tmp/signatureFile1653935437183270228.jar
Problems downloading artifact: osgi.bundle,com.python.pydev.codecompletion,4.5.4.201601292234.
Error reading signed content:/tmp/signatureFile106889934731764251.jar
An error occurred while processing the signatures for the file: /tmp/signatureFile106889934731764251.jar
Problems downloading artifact: osgi.bundle,com.python.pydev.debug,4.5.4.201601292234.
Error reading signed content:/tmp/signatureFile9068867808045510251.jar
An error occurred while processing the signatures for the file: /tmp/signatureFile9068867808045510251.jar
Problems downloading artifact: osgi.bundle,com.python.pydev.fastparser,4.5.4.201601292234.
Error reading signed content:/tmp/signatureFile4356051096777669804.jar
An error occurred while processing the signatures for the file: /tmp/signatureFile4356051096777669804.jar
Problems downloading artifact: osgi.bundle,com.python.pydev.refactoring,4.5.4.201601292234.
Error reading signed content:/tmp/signatureFile7567763792057389909.jar
An error occurred while processing the signatures for the file: /tmp/signatureFile7567763792057389909.jar
Problems downloading artifact: osgi.bundle,org.python.pydev,4.5.4.201601292234.
Error reading signed content:/tmp/signatureFile6685403030330680669.jar
An error occurred while processing the signatures for the file: /tmp/signatureFile6685403030330680669.jar
Problems downloading artifact: osgi.bundle,org.python.pydev.ast,4.5.4.201601292234.
Error reading signed content:/tmp/signatureFile8072627041346437329.jar
An error occurred while processing the signatures for the file: /tmp/signatureFile8072627041346437329.jar
Problems downloading artifact: osgi.bundle,org.python.pydev.core,4.5.4.201601292234.
Error reading signed content:/tmp/signatureFile2089492783574675291.jar
An error occurred while processing the signatures for the file: /tmp/signatureFile2089492783574675291.jar
Problems downloading artifact: osgi.bundle,org.python.pydev.customizations,4.5.4.201601292234.
Error reading signed content:/tmp/signatureFile2865653197501795713.jar
An error occurred while processing the signatures for the file: /tmp/signatureFile2865653197501795713.jar
Problems downloading artifact: osgi.bundle,org.python.pydev.debug,4.5.4.201601292234.
Error reading signed content:/tmp/signatureFile1775095909495668460.jar
An error occurred while processing the signatures for the file: /tmp/signatureFile1775095909495668460.jar
Problems downloading artifact: osgi.bundle,org.python.pydev.django,4.5.4.201601292234.
Error reading signed content:/tmp/signatureFile1452921649446263806.jar
An error occurred while processing the signatures for the file: /tmp/signatureFile1452921649446263806.jar
Problems downloading artifact: org.eclipse.update.feature,org.python.pydev.feature,4.5.4.201601292234.
Error reading signed content:/tmp/signatureFile2451876787350801975.jar
An error occurred while processing the signatures for the file: /tmp/signatureFile2451876787350801975.jar
Problems downloading artifact: osgi.bundle,org.python.pydev.help,4.5.4.201601292234.
Error reading signed content:/tmp/signatureFile7175104755163295006.jar
An error occurred while processing the signatures for the file: /tmp/signatureFile7175104755163295006.jar
Problems downloading artifact: osgi.bundle,org.python.pydev.jython,4.5.4.201601292234.
Error reading signed content:/tmp/signatureFile2106476867846363502.jar
An error occurred while processing the signatures for the file: /tmp/signatureFile2106476867846363502.jar
Problems downloading artifact: osgi.bundle,org.python.pydev.parser,4.5.4.201601292234.
Error reading signed content:/tmp/signatureFile8910039705531253143.jar
An error occurred while processing the signatures for the file: /tmp/signatureFile8910039705531253143.jar
Problems downloading artifact: osgi.bundle,org.python.pydev.refactoring,4.5.4.201601292234.
Error reading signed content:/tmp/signatureFile1647659330788283896.jar
An error occurred while processing the signatures for the file: /tmp/signatureFile1647659330788283896.jar
Problems downloading artifact: osgi.bundle,org.python.pydev.shared_core,4.5.4.201601292234.
Error reading signed content:/tmp/signatureFile3781476889455217861.jar
An error occurred while processing the signatures for the file: /tmp/signatureFile3781476889455217861.jar
Problems downloading artifact: osgi.bundle,org.python.pydev.shared_interactive_console,4.5.4.201601292234.
Error reading signed content:/tmp/signatureFile658497740848883868.jar
An error occurred while processing the signatures for the file: /tmp/signatureFile658497740848883868.jar
Problems downloading artifact: osgi.bundle,org.python.pydev.shared_ui,4.5.4.201601292234.
Error reading signed content:/tmp/signatureFile2627743839460558771.jar
An error occurred while processing the signatures for the file: /tmp/signatureFile2627743839460558771.jar

Do you have any idea about it? I've tried to uncheck "Show only the latest versions of available software" as suggested here "Installing Pydev for eclipse throws error" but no past versions appeared.

Thank you!