The solar panels you're using produce EU (Industrial-Craft Energy Units), but what the Quarry needs is MJ (BuildCraft Minecraft Joule).
The Electrical Engine is part of the Forestry mod, which is no longer part of Tekkit for some reason or another. It performed that necessary conversion from EU to MJ.
There is another block that does this, though! It's called an Energy Link, courtesy of the Power Converters mod, and it's a bit expensive.
It accepts EU from your solar panels and produces BuildCraft energy. Simply wire it up, and connect it to your quarry. You can place it directly next to the quarry, but if you don't, you need at least two pieces of conductive pipe (wooden, then normal) to connect it.
A quarry needs 22 EU/t to run at full efficiency. However, if you use conductive pipes, the Energy Link will drain a whopping 72 EU/t. I'm not sure if this is a bug, or if it's just that the Energy Link can't tell how much MJ the conductive pipes are going to need. Anyway, you should really place the link directly next to the quarry.
Another thing about it is that you can give the Energy Link a Redstone signal, which makes it stop converting energy. This allows you to turn the quarry on and off (with some delay though, the quarry has an internal energy storage).
(Note that if you're playing Tekkit Lite, this block does not exist. However, you have access to several engines that can indirectly be powered by sunlight. Namely, the 4 different Electric Engines that run off EU – effectively replacing the one from Forestry – and the Blulectric Engine from RedPower that runs off blutricity.)
From past experience, number 1 is the answer in most cases, however, I've heard that machines can stop randomly in some versions of Buildcraft (although I haven't seen it personally).
Best Answer
Sharing frames is perfectly fine, as you can see by these three operational overlapping quarries:
Note, however, that stacking quarries, like the two on the left, makes one quarry ineffective. This is because quarries mine in the same pattern, so the second quarry is constantly trying to catch up with the first, not mine new blocks.
Only frames blocks themselves may overlap, tho. If the blocks don't line up, they will get stuck, as you suggest:
Here are two pairs of non-functioning quarries. Even tho neither is trying to place frame blocks in the mining area of the other, they get stuck because the are trying to place frame blocks in the frame area of the other.
Lastly, just for completeness, quarries cannot place frame blocks in the mining area of each other either: