Eclipse Marketplace error: MarketplaceDiscoveryStrategy

Question

I'm behind a local authenticated proxy, so I manually entered my proxy settings in Window>Preferences>General>Network Connections.

After this I was having the same problem as: How do I have to configure the proxy settings so Eclipse can download new plugins?

So I used the suggestion in the above link about clearing the SOCKS proxy, and the error was gone. But now I'm getting a new error:

eclipse.buildId=I20120608-1400
java.version=1.7.0_05
java.vendor=Oracle Corporation
BootLoader constants: OS=win32, ARCH=x86_64, WS=win32, NL=en_US
Framework arguments:  -product org.eclipse.epp.package.java.product
Command-line arguments:  -os win32 -ws win32 -arch x86_64 -product org.eclipse.epp.package.java.product

Error
Sun Nov 18 14:13:14 IST 2012
MarketplaceDiscoveryStrategy failed with an error

org.eclipse.core.runtime.CoreException: Cannot complete request to http://marketplace.eclipse.org/api/p?product=org.eclipse.epp.package.java.product&os=win32&runtime.version=3.8.0.v20120521-2346&client=org.eclipse.epp.mpc.core&java.version=1.7.0_05&product.version=1.5.0.20120131-1544&ws=win32&nl=en_US: http://marketplace.eclipse.org/api/p?product=org.eclipse.epp.package.java.product&os=win32&runtime.version=3.8.0.v20120521-2346&client=org.eclipse.epp.mpc.core&java.version=1.7.0_05&product.version=1.5.0.20120131-1544&ws=win32&nl=en_US
    at org.eclipse.epp.internal.mpc.core.service.RemoteMarketplaceService.processRequest(RemoteMarketplaceService.java:165)
    at org.eclipse.epp.internal.mpc.core.service.RemoteMarketplaceService.processRequest(RemoteMarketplaceService.java:80)
    at org.eclipse.epp.internal.mpc.core.service.DefaultMarketplaceService.listMarkets(DefaultMarketplaceService.java:128)
    at org.eclipse.epp.internal.mpc.core.service.CachingMarketplaceService.listMarkets(CachingMarketplaceService.java:55)
    at org.eclipse.epp.internal.mpc.ui.catalog.MarketplaceDiscoveryStrategy.findMarketplaceCategory(MarketplaceDiscoveryStrategy.java:451)
    at org.eclipse.epp.internal.mpc.ui.catalog.MarketplaceDiscoveryStrategy.performDiscovery(MarketplaceDiscoveryStrategy.java:136)
    at org.eclipse.equinox.internal.p2.discovery.Catalog.performDiscovery(Catalog.java:85)
    at org.eclipse.epp.internal.mpc.ui.catalog.MarketplaceCatalog.performDiscovery(MarketplaceCatalog.java:255)
    at org.eclipse.equinox.internal.p2.ui.discovery.wizards.CatalogViewer$6.run(CatalogViewer.java:569)
    at org.eclipse.jface.operation.ModalContext$ModalContextThread.run(ModalContext.java:121)
Caused by: java.io.FileNotFoundException: http://marketplace.eclipse.org/api/p?product=org.eclipse.epp.package.java.product&os=win32&runtime.version=3.8.0.v20120521-2346&client=org.eclipse.epp.mpc.core&java.version=1.7.0_05&product.version=1.5.0.20120131-1544&ws=win32&nl=en_US
    at org.eclipse.equinox.internal.p2.transport.ecf.RepositoryStatusHelper.checkFileNotFound(RepositoryStatusHelper.java:297)
    at org.eclipse.equinox.internal.p2.transport.ecf.FileReader.checkException(FileReader.java:474)
    at org.eclipse.equinox.internal.p2.transport.ecf.FileReader.sendRetrieveRequest(FileReader.java:431)
    at org.eclipse.equinox.internal.p2.transport.ecf.FileReader.read(FileReader.java:273)
    at org.eclipse.equinox.internal.p2.transport.ecf.RepositoryTransport.stream(RepositoryTransport.java:172)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at org.eclipse.epp.internal.mpc.core.util.AbstractP2TransportFactory.invokeStream(AbstractP2TransportFactory.java:35)
    at org.eclipse.epp.internal.mpc.core.util.TransportFactory$1.stream(TransportFactory.java:69)
    at org.eclipse.epp.internal.mpc.core.service.RemoteMarketplaceService.processRequest(RemoteMarketplaceService.java:141)
    ... 9 more

This is the what I get when I try to run Marketplace. I googled a lot but I can't figure out how to fix it.

Any help?