The game works perfectly for me except for one thing; I can't shoot enemies who are near trees. If they are on the other side of a tree, even though they are not being the trunk, or the branches, when I hover over them with the cursor, the status bar says "tree" and won't allow me to click to attack the enemy. However, the enemy has no such problem.

It's not so bad early on, but it's really becoming a pain in forest areas where my only choice is to get up close and melee.

Weirdly, if I right-click, it shows the description of the monster, so it does recognise the monster is there in some ways.

Anyone else had this problem and know of a fix?

Getting the manual targeting to shoot past trees can be an issue sometimes. However, if they have line of fire to you, that means you also have line of fire to them.

One solution is to move toward a clear area so they emerge into the open.

Another solution is to let the game auto-target for you. Use the "a" key to make an attack, or the "s" key to cast whatever spell is set as the current quick-spell (or attack if the character is out of mana or no quick spell is set). If the cursor is on an enemy, the game will target that enemy, while if the cursor isn't on an enemy, the game will target the closest visible enemy. If no enemy is in view, the arrow/spell is fired straight ahead. You may have to do some field-of-view manipulation to get the game to pick your desired target, turning so closer enemies than your desired target aren't in view, but it can be done. Iirc, enemies near the very edges of your view appear a little bit closer than when they are in the center, which can help you target specific creatures.

You can hit "S" or "A" to let the engine pick an enemy that can be hit.
However, magic is often blocked by objects where arrows can hit.
But moving often is the best answer