You really need to read this → http://forum.mikrotik.com/t/using-routeros-to-vlan-your-network/126489/1
You cannot have more than one untagged pvid assigned to any port and thus this fails
/interface bridge vlan
add bridge=Bridge-LAN tagged=Bridge-LAN,ether8-test_bablu untagged=ether7-out_test_bablu vlan-ids=1833,3375,3376
should be for example:
/interface bridge vlan
add bridge=Bridge-LAN tagged=Bridge-LAN,ether8-test_bablu untagged=ether7-out_test_bablu vlan-ids=3375
add bridge=Bridge-LAN tagged=Bridge-LAN,ether8-test_bablu vlan-ids=1833,3376