我用Eclipse 3.3.1 版本，
开发Java 相关应用，
今天想要开发PHP ，要下载PDT
"Help -> Install New Software"
URL: 打入下面
http://download.eclipse.org/tools/pdt/updates/nightly
http://download.eclipse.org/tools/pdt/updates/3.2-nightly
也上网找过资料，
统统都不行
Network connection problems encountered during search.
Unable to access "http://download.eclipse.org/tools/pdt/updates/nightly".
Error parsing site stream. [The XML stream is not a valid default "site.xml" file. The root tag is not site.]
The XML stream is not a valid default "site.xml" file. The root tag is not site.
Error parsing site stream. [The XML stream is not a valid default "site.xml" file. The root tag is not site.]
The XML stream is not a valid default "site.xml" file. The root tag is not site.
请问该怎么作呢？