I hate IIS/ASP.
UNSPECIFIED ERROR !!!! WARNING DANGER WILL ROBINSON !!!.
How about “DANGER !!, you are about to step off a cliff … at line 1045″ 
I have copy/pasted the information from the link (mainly because I text search this site for my own notes, and partially because I’m covering if the original site disappears)
Procedures for fixing the dreaded 8004005 Error when using ASP to connect to an Access Database (on NT only, this has not been tested on Win 2000):
Steps to do this:
Part I
· Right-click My Computer, and then click Properties.
· Select the Environment tab, and then click on any of the existing variables in the System section. Both the variable name and value appear in the text boxes of the System Properties dialog box (at the bottom of the dialog box).
· Delete the variable name in the Variable text box and type in TEMP.
· Delete the text in the Value text box and type C:\TEMP.
· Click the SET button, and the variable is added to the System section.
Part II
· Again, select any of the existing variables in the System section.
· Delete the value in the Variable text box and replace it with the word TMP
· Delete the value in the Value text box and replace it with C:\TEMP
· Click the SET button, and the variable is added to the System section
Part III
· Go to the C:\TEMP directory. Right click and choose properties. Select permissions. Ensure that your IUSR account has Read, Write, and Change access. If the IUSR is not listed, add it. (The IUSR account is the anonymous Web account: IUSR_machinename, where machinename is the name of your Web server.)
Part IV
· You will need to REBOOT the server for these changes to take affect.
As a precaution, make sure IUSR has Read/Write permissions on the database you are using as well.