Your problem is outside the realm of my experience, but I did do some searches to see what I came up with. Perhaps they can lead you in the right direction.
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On another discussion forum, I saw this possible solution:
MS IIS 5.0 has problems handling a specific form of URL ending with "ida".
The extension ida has been taken from the Bugtraq posting "IIS revealing webdirectories"
The problem causes 2 kind of results.
The one result is that the server responds with amessage:
"URL String too long"; "Cannot find the specified path"
The other error causes the server to terminate with an Access Violation.
When the server "Access violates" it displays as last message:
Temporary Solution:
Enable IIS to check for URL strings that are too long and block them.
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I then ran across this solution:
If you encounter the error message, “The system cannot find the path specified. The system cannot find the path specified.", it's an indicator that you have not properly applied the changes required for utilizing an "external" SMTP server.
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This link took me to a security update that mentioned similar problems:
http://www.macvillage.net/news/articles/99305173881246.shtml
(REMOVE SPACES from the pasted URL.)
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Good luck,
Maxwell