In a new project, if you check the prerequisites box for .NET 4.0, and haven't yet saved the project file, Advanced Installer 9.8 reports that it saved the project, but it crashes (reports exception) when trying to download the resouce files.
[EXCEPTION_UNHANDLED] (0xc0000005) at address [0x0040942f]
Advanced Installer 9.8 build 48877
*** Stack Trace (x86) ***
[0x0040942f] -----
The error does not occur if the project file is saved first before downloading.