I get the following error when I try to install Emplode V2.00 to Windows 98.

1155 File C:\My Documents\Empeg Stuff\car-emplode-v2.00\INSTMSIA.EXE not found

INSTMSIA.EXE is the file to install the MSI installer. I do recall someone saying that the new install is utilizing the option in Installshield 8 to get a new version of the installer from the internet. If I were to guess (since I'm not exactly an msi guru here) I'd say that the mechanism for downloading the msi engine isn't working. There must be a way to manually download the msi engine and install it, and this I suspect would fix your problem.

I notice that in the downloaded directory for the previous versions the files
instmsiA.exe
instmsiW.exe
do exist

The "A" and "W" are different version of the MSI install engine for 95 and NT codestreams, though I don't remember which is which.