The activation servers for CS2 have been decommissioned. Your current copy is unusable.
For legitimate CS2 owners, Adobe has posted a version of CS2 that requires no activation. You just have to download it and use the special serial number provided for this purpose.
Adobe has disabled the activation server for CS2 products, including Acrobat 7, because of a technical issue. These products were released more than seven years ago, do not run on many modern operating systems, and are no longer supported.
Adobe strongly advises against running unsupported and outdated software. The serial numbers below should only be used by customers who legitimately purchased CS2 or Acrobat 7 and need to maintain their current use of these products.