missile object.dll error was caused by using a wrong editor amoung other things - if you remove weapondata.dat from the SF "weapons" folder does it then load up?
Drop tank names have to be specific to the name show in the jets xxxx_data.ini ie this if from an f-104
[RightWingtipStation]
SystemType=WEAPON_STATION
StationID=2
StationGroupID=1
StationType=EXTERNAL
AttachmentPosition=3.304,-0.176,-0.513
AttachmentAngles=0.0,0.0,-90.0
LoadLimit=250.0
AllowedWeaponClass=IRM,FT
AttachmentType=NATO,W_GERMANY
ModelNodeName=
PylonMass=
LaunchRailNodeName=missile_rail_wt_right
LaunchRailHeight=0.15
LaunchRailMass=24.95
FuelTankName=Tank170_F104 <------- the drop tank it can use
[LeftWingStation]
SystemType=WEAPON_STATION
StationID=3
StationGroupID=2
StationType=EXTERNAL
AttachmentPosition=-1.883,0.400,-0.665
AttachmentAngles=0.0,-3.0,0.0
EjectVelocity=0.0,0.0,-2.0
LoadLimit=500
AllowedWeaponClass=BOMB,RP,CGR,ASM,IFP,FT
AttachmentType=NATO,W_GERMANY
ModelNodeName=pylon_left_inner
PylonMass=72.58
PylonDragArea=0.02
FuelTankName=Tank195_F104 <------- the drop tank it can use
hope that helps