Terraforming near water causes CTD

[EDGE4194]

I hate to add ANOTHER post about a CTD problem, but I need suggestions. I've read every post on CTDs and tried every trick. I have been playing the same region for two years on the same PC (Win XP) with no problems. I reformatted my HD, installed Win7, installed SC4 & the update, and copied over my plugins and region. I discovered CTDs occur whenever terraforming near water (within about 6-8 tiles). I figured it must be Win7, so I installed all to a fresh XP partition. CTDs again when terraforming near water.
I have the SAME hardware, SAME plugins (nothing new), and running SAME OS. (the only things new are the new OS installs)
Here's what I've discovered so far...
  * all tiles with water in region are affected (built up or not)
  * mayor mode, god mode, or road tool used within 6-8 tiles of water causes crash
  * when i load the maxis "fairview" region and terraform, no CTDs, so it seems to be only my region.
  * when i import one of my city tiles to Fairview region, the CTDs continue
  * i even used a sea level mod to remove the water, but it still crashes if terraforming within 6 or 8 tiles of where the water was.

I don't know what else to try. Does anyone have any other suggestions or anything that i overlooked? 

[mtg]

What you might have overlooked is that MS XP is not that bad at all, could it not be that XP does all the tricks you want it to preform? Are Vista and now the new 7, not just moneymaking products? it's just an idea...

[turtle]

The only thing I can think of is perhaps there are some conflicting beach mods or something like that. But since you copied a working plugin folder, that's probably not it. Good luck, though

[EDGE4194]

on one hand I'm glad to see other people are stumped as well, on the other, I guess I still have work ahead of me trying to figure out. turtle- no beach mod but i even removed the same water mod i've been using for years, just to see and it didn't affect it. mtg- the point was my problem exists in both OSes. There is obviously something I am overlooking. Once I figure it out i will post back here with the result...