Batch replacing FITS keyword

[Astrocava]

I have a problem when trying to register some images taken with Firecapture.

Code: [Select]

Generating registered image
Homographic Projection / Lanczos-3 LUT interpolation, c=0.30: done
Registration successful.
Writing output file: K:/Astronomía/Brutos/CIELO PROFUNDO/ASI/DeepSky/150714_224844/2014-07-15-2248.7-R_0029_r.fit
*** PCL Exception: PCL FITS Format Support: Error writing FITS header keyword:
K:/Astronomía/Brutos/CIELO PROFUNDO/ASI/DeepSky/150714_224844/2014-07-15-2248.7-R_0029_r.fit
CFITSIO error message stack:
01 : Character 15 in this keyword is illegal. Hex Value = FFFFFFB0
02 : HIERARCH TEMP(°C) = '24,2    '                                                 

I need to replace TEMP(ºC) by TEMP(C) in several files. Is any tool available to make this task easier and faster than using FITSheader  for every file?

Thanks in advance,

Sergio