It's just an error in the 3.6.7 MediaVP weapons.tbl. I had the same problem earlier this morning. The default shockwave name is "shockwave.pof" but it's not required. If a 3-D shockwave model is specified in the tbls though then it's required. That's the problem here, the tbls require it but the model isn't included. As it's the default shockwave name though the tbls are requesting it in error since they should use the default or specify a new one.
Just edit weapons.tbl and remove all "$Shockwave Model:" lines. That will fix it until the VPs get updated.