If the shockshunds work in other levels you're probably just running out of memory.
Perhaps you can delete an equivalent memory's usage of another sprite. Are there other sprites in the level that you can do without? delete a couple and leave the shockshunds in. See if that works.
I have the exact same problem in my Keen 4 mod. Whenever my Invincible, Dangerous Bounder (who is now the Mad Mushroom) comes in-screen, the game crashes in the same way, with those thin black&white lines across the screen. This is before I changed any of the levels, so it might not be a memory issue. By removing the Invincible patch, the game worked fine.
Mh, okay, but I changed no enemy of the original keen 5, so I don't get it why suddenly the game crashes. I tried to remember, what I changed in the last few days, but this was just graphic-changing, no patching or something like this.
If you're at all worried about the patchfile possibly being the cause, you could just run the .exe directly, skipping the load patch part. If it still crashes the same way, then you know its not the patches.
As a side note, the 'thin black lines' freeze-crash occurs when data is written to the players... uh.. memory stuff in the wrong place. I have found this often happens with sloppily patched sprites when something causes them to put their data stuff where it shouldn't be. This should never happen with unpatched sprites, but occasionally does when another sprite patch messes up a 'clean' sprite.
The only cure I have found is to make a level with just that sprite, remove all (Or as many as possible) patches and slowly add them back, looking for the one that causes the problem. The buggy patch can usually be fixed.
