Desastersoft original developers left business a long time ago, selling their site and files for a guy apparently not involved with code program and flight games,
who keep selling this campaigns, but don't providing support for install issues - this campaigns use custom .DLL.
When TF 4.50 was released the compatibility was broken due this custom .DLL, Desastersoft don't solve the issue, but an ATAG guy make a fix.
Based on all this, better forget these campaign and consider then now as... "history". :))