Is this an issue with the compact solar panel add on? Or IC2? What do I need to do to fix this?
Any help would be appreciated.
One of your mods is overriding IC2 1.110 API with it's outdated version of IC2 API. Delete every single /ic2/api file in each mod file except the one in IC2.
If problem persists, head to Compact Solars thread.
In reality, the problem is inside of Compact Solars, the IC2 update to 1.110 changed the wrench API a bit and ended up breaking the addons that add machines. cpw hasn't, to my knowledge, fixed the solars to take into account the new internal wrench mechanics.