Sorry for the late response but it was unsure if the problem was resolved in previous posts.
We did the following test with version 6.0.6.
1. We created a key ring in Windows 2003 x86
2. We created a DSA 2048 key pair
3. We encrypted a file on that server with that key pair
4. We exported by saving public and private key from the PGP key ring interface
5. We created a new key ring on Windows 2008 x64
6. We imported the files into that key ring
7. We read and decrypted the encrypted file with the new key ring successfully
We also tested to export the VisualCron keyring by choosing export on first server and import on new server. Same result.
As keys are, whether they are exported to file in pgp format or the actual key ring is exported untouched. This means that it should not matter where the file goes as the format is standard.
Most likely the password is different but we do not exclude that another error could create this message. Perhaps, if the file is not found or permissions are missing.
We suggest that you try to reproduce this with latest version. Also, create the first key in VisualCron instead of importing it. Test it on the first server first. Then export in any format you like - then import it and try on new server.