gdb cannot print object casted to a pointer of certain class

[Sp3cial K]

Has anyone encountered a problem where ptype prints out the class info in 
most frames, but it complaints "Type xxx has no component named xxx." in one 
frame?  Ironically, the frame where it doesn't print out correctly is in a 
function of that class!

Also, when I tried to print out an object casted to that class, as follows:
p *(xxx *)0x12345678
it complains:
A parse error in expression, near `)0x12345678'

But if I switch to another frame, then it prints out fine...

Any help will be greatly appreciated!

Thanks,

Special K