I am not sure but once I saw such post few months back explaining this but if you have a – in your moss portal link or dns, your send link in email functionality will not work properly because IE change the – to %2d. To fix this issue you need to edit core .JS file
Core.js file is placed at
System Drive:\Program Files\Common Files\Microsoft Shared\web server extensions\12\TEMPLATE\LAYOUTS\1033
Open Core.js in notepad
If you have customized core.js before this search for L_SendToEmail_Text
if you have not customized core.js simply jump to line 3309
all you need to do is to encode the url to show – instead of %2d. unescapeProperly method encodes the URL.
Simple press enter on line 3309
fileUrl = unescapeProperly(fileUrl);
If you wanted to test it add alert before and after fileURL variable.
Save Core.js and Refresh the page.
Go to a document library and using document drop down click Send To -> Send Link in Email
I hope this will solve your problem.
Jerry
Jerry Yasir's Blog 
Thanks just for sharing with us. Totally nice place with the wonderful material. Interesting “Send Link in Email can cause problem if site URL has – e.g. my-portal.com Jerry Yasir”. Make sure you upgrade on a regular basis whenever you can simply because many of us want much more.