You can make curry without chili. Black pepper is an alternative.
Here are the spices I would put in an Indonesian lamb curry:
cumin (whole)
coriander (whole)
black pepper (whole)
nutmeg (whole)
garlic
shallots (buy from Indian shop)
galangal (fresh or frozen)
ginger (fresh)
turmeric (preferably fresh)
star anise (whole)
cinnamon (whole, buy from Indian shop, supermarkets are a rip off)
cardamom (whole)
lemon grass
kaffir lime leaves (dried or frozen, they sell frozen in Chinese supermarkets, dried in jars)
daun salam leaves (very hard to find, possible in Chinese supermarkets)
Basically grind 1 tsp cumin, 1 tbsp coriander, half nutmeg, 1 tbsp (may be too spicy, you can use less) black pepper. You could grind in a spice mill, food processor, or mortar & pestle. Then add 150g peeled shallots, 6 garlic cloves, 1 inch of peeled galangal (optional, if you can't find it), same of peeled ginger root, 1/2 inch of fresh peeled turmeric (it's a much thinner root than ginger, this is about 1/2 tsp's worth if you use dried). Add one red Thai (or other) chili for a bit of heat, about half-a-dozen for a more authentic (HOT) spiciness. Blend to a smooth paste.
Fry in 1 tbsp of oil, then add the kaffir lime leaves, a 4-inch cinnamon stick, 5 whole star anise, 1 or 2 heavily bruised lemon grass stalks (definitely two if you don't have the lime leaves), 5 bruised cardamom pods, daun salam leaves, and fry until fragrant.
Then add about 1kg of lamb (chopped leg of lamb works, you could also try lamb shanks, stewing lamb, etc.), brown in the sauce. When browned, add a can of coconut milk, and perhaps half a can of water (you could add more coconut milk, but I find it too rich). Bring to a simmer, then cook, covered, until tender (you could put it in oven at about 150C if you prefer).
Finish with coriander leaves and a squeeze of lime juice.