Why can’t I spend the destiny points

The most important things to remember are:
The Lore-Master is not a Damage Dealer
The Lore-Master is not a Healer

Your role is crowd control and supporter, which means you check which target can hurt your group most and immobilize it, usually with your Blinding Flash which is your most important skill in every group and instance.

You have to check that noone attacks this target so he will actually stay stunned. If the target you want to stun already gets attacked, just switch to the next important free target.

Priority targets are:

• Strong enemy damage dealers
• Anything attacking your healer
• Enemy healers

The second most important skill in your bar will be Share the Power which you can use to support your healer. Especially in later instances your healers will run out of energy quite fast, especially in a less experienced group.

I do not recommend pets in group since they easily attract more enemies than your party can handle.

Other usefull skills:

• Beacon of Hope to heal your healer in case of emergency
• Power of Knowledge to gain power you can then transfer to your healer
• Sticky Tar allows your casters/ranged players to kite the enemy more easily
• Herb Lore is especially usefull if there are too many enemies for your group to control, it allows you to easily root a whole group of enemies. Keep in mind that it's useless against ranged enemies though.
• Sign of Power: Righteousness is important against enemies that tend to stun a lot, in which case you should keep it up all the time on your healer.

All the other skills are nice to have but in groups you have to master the above mentioned skills and make sure you fullfill those tasks before you can expand your play to use all the other skills.

Lore-Master is an even less obvious character than healers, you usually don't see when he does anything, you only see when he doesn't do what he was supposed to do.

I think the lore master is the hardest solo character since it's extremely weak in melee. The pets make it easier but you still tend to die quite fast if you make even a slight mistake.

Oh, that reminds me of another important point:
The Lore-Master is not a Tank, but can be used as a good fighter if traited right. so in some cases you do not need to run in circles, if traited differently though, it is suggested that you do run in circles

LOTRO Destiny Points (DP) can be earned by playing as Monster or by gaining levels after level 10 (200 destiny points each level).

Destiny Points can be spent in two ways:

• In Monster Play (buy skill, traits, play as Troll, etc.)
• Buying Player Perks

The are many useful perks that can help your character leveling faster, increase movement speed, armor and so on.

I suggest you to look at LOTRO Wiki for more info.