RCT2 SAVED GAME PROMBLEMS

I was wondering if ANYBODY COULD HELP ME as to why every time I try to open a saved game file in rct2, I get the message:"Unable to load data. Missing object data, ID: (then a bunch of numbers and letters.)
I have no clue why it's doing this, but as you can imagine it is VERY FRUSTRATING!!!!!![confused][:(!][dunno]. Thanks in advance if you reply.[:)]

is it dowload park, if yes it missing some data files in the park (sceanery).

I have the same problem every now and then, make sure you have both add-ons and if the park still wont open just keep it and try to download other parks, once their scenery get added then try back because you may have the piece you were missing in the first place

thanks