As you can see, I have simconnect from SP2, so that's not problem of not having it (how you said, two simconnects don't work together).
It's BECAUSE you have several Simconnect together that you might have problems!
As I've said, when everything's working correctly, it IS ( better say "it should be" ) possible for two versions of the same .DLL to run together in the same process (this is called Windows Side-by-Side loading). However, this sometimes won't work and the following might happen:
1) Another addon using the old versions will load *before* others, and will let the sim being "stuck" on the old version, not trying to load ALSO the newer one, required by another addon (the Addon Manager *requires* the SP2 version), so this will result in the Simconnect_text() error message, because the Addon Mananger cannot find that API call, which has been added in the FSX SP1 version of the library, but apparently, an addon using the RTM (Original) version has prevented the sim from loading the newest ones together with the original one.
This can be FIXED by loading the Addon Manager first, which is what our installer does anyway, by placing it on top of the DLL.XML file.
2) Even if the problem of the Simconnect_text() error goes away, that doesn't ensure the two .DLLs won't cause other issues when loaded together in memory because, the whole point of the Side-by-Side system is they SHOULD have been loaded together automatically, without any need to re-arrange the loading order. Re-arranging the loading order only side-stepped the problem but, if Windows hasn't allowed to load them together for some reason, it's possible they *will* load, but *will* then crash once loaded, since something happened to your Windows install that prevented the Side-by-side system to work correctly.
Unfortunately, it's not a very reliable system, and even Microsoft is moving away from it: they used it for the VC++ runtimes libraries since 2005, now they went back to a non-Side-by-Side system for VC++ 2013 and up. But unfortunately, FSX is made like that, and nobody is going to fix it.
The REAL fix, to prevent all potential conflicts between modules, is that developers would STOP using the RTM or the SP1 version of Simconnect, and moved on the SP2/Xpack version, which is the latest for FSX. Hardly anyone is still using FSX RTM or FSX SP1, so I really cannot see why any developer would still need to support them.
