PrBoom+ R_InitTextures: How do I fix it?

[tubs]

Every time I load up my wad in Boom, it shows this error: 

Here's a link to my wad:https://www.mediafire.com/file/0j9e2b6igodm8nj/testmap.wad/file

[Aurelius]

Some of the textures are not properly added to the TEXTUREx lump. You should choose all textures (between PP_START and PP_END) that weren't part of the texture pack you took the TEXTUREx lump from, and add them to it (right-click -> graphic -> add to TEXTUREx). Alternatively you could just delete the PNAMES and TEXTURE1 lumps and generate them from scratch by choosing all textures (again, between PP_START and PP_END) and doing the same thing (and either choosing the "Import from base resource archive option" or renaming the generated TEXTURE1 lump as TEXTURE2). All animations and switches should work the same as they are governed by their own lumps. More information here.

 

To address your other issue, move your ROCKBLU between the PP_START and PP_END markers and add it to the TEXTUREx lump.

[azerty]

I think it mean the textures aren't loaded correctly so when he tries to render them it fails. Try to look if you added the textures properly