So I exported all my products by using the magento exporter under
System -> Import-Export -> Dataflow Profile -> Export all products
and then on the other magento installation:
System -> Import-Export -> Dataflow Profile -> Import all products
But the products where not imported, even though the import claims to be successfull. There were a few errors though, like missing pictures or sku on some products.
Is the product exporter not working in general or was it my fault?