OpenPGP import of a key fails

The following key makes the import operation fail with error code 400:

-----BEGIN PGP PRIVATE KEY BLOCK-----

xVcEZtWrxhYJKwYBBAHaRw8BAQdAN0sGM7khjJrjiEbcdT74LgnGlj/+whhn8mpF
AaVWTGoAAPda3dw1342A/NgznsY59v8RtoTv+Rw5QBPHVrZAEDW2Ea3NJVRlc3Qg
c2lnbmluZzEwIGtleSA8dGVzdEBleGFtcGxlLmNvbT7CjQQQFggANQIZAQUCZtWr
xgIbAwgLCQgHCg0MCwUVCgkICwIWAhYhBCLf7Tv3QSiPD9i+GLtS8sTQexd1AAoJ
ELtS8sTQexd1VZYA/1T1tFmsvP5uDM6dfphSXKbKFSIZleWdZejddCZHoYC7AP4n
+iIHDqHSqqzMNHN1u01UXzKGVC/QBLPAPCjpR3GtDQ==
=Cva8
-----END PGP PRIVATE KEY BLOCK-----