PGP TO GPG key import problems

[Craig Stratton]

Hi,
i want to import public and private keys from PGP 5.5.3i into GPG 1.2.1 and
"seamlessly" carry on sending mail from an automated system.

I have got an ASC export file with public and private keys in from PGP.
I have imported using gpg --allow-secret-key-import --import FILE

However, i have a couple of "issues".
gpg: WARNING: unsafe permissions on homedir ....
gpg: WARNING: using insecure memory!
gpg: please see http://www.gnupg.org/faq.html for more information

OK, i can see what i need to do for these, but

gpg: protection algorithm 1 (IDEA) is not supported
gpg: the IDEA cipher plugin is not present
gpg: please see http://www.gnupg.org/why-not-idea.html for more information
gpg: no default secret key: unknown cipher algorithm
gpg: [stdin]: clearsign failed: unknown cipher algorithm

But what can i do about this ?
The keys are RSA/IDEA combination. How can i convert them from within gpg to
use something else ?

I am sure that the entity that i send the signed mails can accept different
ciphers, but is that dependent on their version of my public key ?
If i manage to use a different cipher, will they carry on working fine
without any intervention required ?

I don't use encryption day to day, i am writing an automated interface to
replace a manual process.
It works fine when i generate new keys, but obviously now i need to import
the correct ones to go live.

I am looking for some easy-to-follow steps that will walk me through the
process.
Once i installed the IDEA extension, then i lost the IDEA messages, but i
would rather do it "properly".

Thanks in advance.
Craig