I again have a silly question:) At attempt to set a label to tapes, amlabel 
gives out a following mistake:

amlabel: label svn16 doesn't match labelstr "^svn[1-25][1-25]*$"
amlabel: label svn17 doesn't match labelstr "^svn[1-25][1-25]*$"
amlabel: label svn18 doesn't match labelstr "^svn[1-25][1-25]*$"
amlabel: label svn19 doesn't match labelstr "^svn[1-25][1-25]*$"
amlabel: label svn20 doesn't match labelstr "^svn[1-25][1-25]*$"

in amanda.conf labelstr has a following appearance:
labelstr "^svn[1-25][1-25]*$"

What I not so do?