Mac program files on the Internet are normally encoded MacBinary (.bin) or BinHex (.hqx) for protection. Sometimes they are just compressed (StuffIt = .sit). Use StuffIt Expander for the decoding and/or decompression (drag the file onto the StuffIt Expander icon).
Unfortunately, the browsers capable of running under Mac OS 9.x are not going to work well with all web pages.
iCab could possibly be an alternative worth trying.
Jan