Comment 5 for bug 704609

In case it helps:

(1) The DLLs (wer.dll for Windows Error Reporting and ieshims.dll for supposedly something Internet Explorer related) are not present on Windows systems prior to Vista according to http://social.technet.microsoft.com/Forums/en-US/w7itproinstall/thread/8a751f65-ade9-4b8b-a3d3-c720ccbd3d2c/#d8f1e6b4-a105-4bcb-aeb2-1894175960e7

(2) Unrelated, but some technical stuff (and some ranting about that) for what side-by-side configuration is supposed to do can be found at http://buffered.io/2008/05/17/resolving-side-by-side-configuration-issues/

(3) Because of (1), you should probably ship the DLLs with the installation package or (better) make them not a dependency at all.