Problems with attached pdf files - Acrobat 8

Recently I have  changed my pdf-reader (from Adobe 7.0 to Acrobat Reader 8.0) and since my attached pdf - files can’t be opened. The error message: This Url \E:\ … could not be opened

I have tried to replace the link to my attached files and have even deleted the PDF Folder in my library, but without any success.

Can there be a problem with an Acrobat Addin? When I try to open the pdfs in eht Win explorer they can be opened without any problem.

Thx for help