mksysb restore errors

goodafternoon people.
here are a couple of error messages I get during restore of mksysb from a AIX F80 to a F50. I have verified blocksize and have set them to 1024 which matches both the systems.
backup system is F80 and restore system is F50. Both are 4.3.3 ML10 level

Upon executing via smitty to list content of tape the following errors are displayed

restore - 0511-262 Read an expected end of file
cat: 0652-050 Cannot open tapeblksz
ksh[47]: test:0403-004 Specify a parameter with this command

would appreciate assistance

Thnx

afternoon,
turned out my tape was corrupt. since 4.3's dont have tape validation entries I tried it on my AIX 5.x and it displayed a 0512-063