以下消息是什么意思？指示的行有一个命令，它与我如何调用定理、引理等有关。
Package: pifont 2005/04/12 PSNFSS-v9.2a Pi font support (SPQR)
LaTeX Font Info: Try loading font information for U+pzd on input line 63.
("C:\Program Files\MiKTeX 2.9\tex\latex\psnfss\upzd.fd"
File: upzd.fd 2001/06/04 font definitions for U/pzd.
)
LaTeX Font Info: Try loading font information for U+psy on input line 64.
("C:\Program Files\MiKTeX 2.9\tex\latex\psnfss\upsy.fd"
File: upsy.fd 2001/06/04 font definitions for U/psy.
)
! Font U/psy/m/n/10.95=psyr at 10.95pt not loadable: Metric (TFM) file not found.
<to be read again>
relax
l.64 {\Pifont{psy}
}