I am unable to export my gpg keys from Machine#1 to Machine#2 (See below). I have an error message when I try to import the secret key
error sending to agent: Permission denied
I do not know what this means and can find on explaination on the web. The Key ID being imported seems wrong and, when I look into the .gnupg directory the zero length agent files seem wrong. What am I doing wrong. The process that I used to export and then import the keys are documented below.

Machine#1

tim@Machine#1:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 16.04.4 LTS
Release:        16.04
Codename:       xenial
tim@Machine#1:~$

    tim@Machine#1:~$ ls -l .gnupg
    total 36
    -rw------- 1 tim tim 9398 Feb 11 20:08 gpg.conf
    -rw------- 1 tim tim 2398 Mar 17 18:15 pubring.gpg
    -rw------- 1 tim tim 2398 Mar 17 18:15 pubring.gpg~
    -rw------- 1 tim tim  600 May 24 18:49 random_seed
    -rw------- 1 tim tim 5186 Mar 17 18:15 secring.gpg
    -rw------- 1 tim tim 1360 Mar 17 18:15 trustdb.gpg
    tim@Machine#1:~$


    tim@Machine#1:~$ gpg --version
    gpg (GnuPG) 1.4.20
    Copyright (C) 2015 Free Software Foundation, Inc.
    License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
    This is free software: you are free to change and redistribute it.
    There is NO WARRANTY, to the extent permitted by law.

    Home: ~/.gnupg
    Supported algorithms:
    Pubkey: RSA, RSA-E, RSA-S, ELG-E, DSA
    Cipher: IDEA, 3DES, CAST5, BLOWFISH, AES, AES192, AES256, TWOFISH,
            CAMELLIA128, CAMELLIA192, CAMELLIA256
    Hash: MD5, SHA1, RIPEMD160, SHA256, SHA384, SHA512, SHA224
    Compression: Uncompressed, ZIP, ZLIB, BZIP2
    tim@Machine#1:~$

Machine#2

tim@Machine#2:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 18.04.2 LTS
Release:        18.04
Codename:       bionic
tim@Machine#2:~$

    tim@Machine2:~$ gpg --version
    gpg (GnuPG) 2.2.4
    libgcrypt 1.8.1
    Copyright (C) 2017 Free Software Foundation, Inc.
    License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>
    This is free software: you are free to change and redistribute it.
    There is NO WARRANTY, to the extent permitted by law.

    Home: /home/tim/.gnupg
    Supported algorithms:
    Pubkey: RSA, ELG, DSA, ECDH, ECDSA, EDDSA
    Cipher: IDEA, 3DES, CAST5, BLOWFISH, AES, AES192, AES256, TWOFISH,
            CAMELLIA128, CAMELLIA192, CAMELLIA256
    Hash: SHA1, RIPEMD160, SHA256, SHA384, SHA512, SHA224
    Compression: Uncompressed, ZIP, ZLIB, BZIP2
    tim@Machine2:~$

    tim@Hear2Read2:~$ gpg --fingerprint
    /home/tim/.gnupg/pubring.gpg
    ----------------------------
    pub   2048R/83EB69F3 2020-02-11
        Key fingerprint = 0343 CF48 7E72 4B8C C8BE  51C0 47FB 83BC 83EB 69F3
    uid                  Timothy White (Developer) <tim@hear2read.org>
    sub   2048R/2F1932FB 2020-02-11

    pub   2048R/FE4572BD 2020-03-17
        Key fingerprint = AA0D 9A6B 55E7 DBC1 0FB5  93EF 9866 EEF5 FE45 72BD
    uid                  Timothy White <flite@hear2read.org>
    sub   2048R/0134F557 2020-03-17

    //.gnupg listing was done after the import failed.
    tim@Machine#2:~$ ls -l .gnupg
    total 20
    srwx------ 1 tim tim    0 May 30 17:48 S.gpg-agent
    srwx------ 1 tim tim    0 May 24 18:53 S.gpg-agent.browser
    srwx------ 1 tim tim    0 May 24 18:53 S.gpg-agent.extra
    srwx------ 1 tim tim    0 May 24 18:53 S.gpg-agent.ssh
    drwx------ 2 tim tim 4096 May 24 18:53 private-keys-v1.d
    -rw-rw-r-- 1 tim tim 4170 May 30 17:43 pubring.kbx
    -rw-rw-r-- 1 tim tim 2794 May 30 17:43 pubring.kbx~
    -rw------- 1 tim tim 1200 May 24 18:53 trustdb.gpg
    tim@Machine#2:~$

Export Keys from Machine#1

    tim@Machine#1:~$ gpg --armor --export --output keys_pub.gpg
    tim@Machine#1:~$ gpg --armor --export-secret-keys --output keys_sec.gpg

gpg files are copied to Machine#2

Import Keys to Machine#2

    tim@Machine#2:~$ gpg --import keys_pub.gpg
    gpg: key 47FB83BC83EB69F3: public key "Timothy White (Developer) <tim@hear2read.org>" imported
    gpg: key 9866EEF5FE4572BD: public key "Timothy White <flite@hear2read.org>" imported
    gpg: Total number processed: 2
    gpg:               imported: 2

    tim@Machine#2:~$ gpg --import keys_sec.gpg
    gpg: key 47FB83BC83EB69F3: "Timothy White (Developer) <tim@hear2read.org>" not changed
    gpg: key 47FB83BC83EB69F3/47FB83BC83EB69F3: error sending to agent: Permission denied
    gpg: error building skey array: Permission denied
    gpg: key 9866EEF5FE4572BD: "Timothy White <flite@hear2read.org>" not changed
    gpg: key 9866EEF5FE4572BD/9866EEF5FE4572BD: error sending to agent: Permission denied
    gpg: error building skey array: Permission denied
    gpg: Total number processed: 2
    gpg:              unchanged: 2
    gpg:       secret keys read: 2
    tim@Machine#2:~$