Several possibilities here:
1. contact the creator, make him aware of the issues and hope he'll fix them.
or
2. finding the missing textures (and props if necessary) and either including them into the bsp or having them downloadable directly from the server
the 2nd possibility should only be used if there won't be an update from the creator.
A few issues you possibly run into with this:
- packing files into the bsp changes CRC, so if the map allready spread in the community
(which is the case here, especially since some ppl only patched 4.1 to 4.2 and 4.2.1)
this would cause a lot of "map differing from server" errors
- renaming the map could cause more issues then it solves, it's kinda tricky to do it without breaking the cubemaps, or increasing the filesize drastically because of duplicated cubemap textures.
- if you choose to have the textures/materials downloading directly from the server, make sure there is no conflict with an existing texture or material in the mod.
BTW: if you need to find out material names of a prop, open the .mdl file with a hex editor (e.g. PSPad), scroll down to the bottom. there should be the name of the materials and also the path where they should be located.