Thank you. I have consulted with the hosting providers and they have confirmed that GD and Mbstring are embedded. I have checked this:
gd
GD Support enabled
GD Version bundled (2.1.0 compatible)
FreeType Support enabled
FreeType Linkage with freetype
FreeType Version 2.3.11
GIF Read Support enabled
GIF Create Support enabled
JPEG Support enabled
libJPEG Version 6b
PNG Support enabled
libPNG Version 1.2.49
WBMP Support enabled
XPM Support enabled
libXpm Version 30411
XBM Support enabled
Directive Local Value Master Value
gd.jpeg_ignore_warning 0 0
mbstring
Multibyte Support enabled
Multibyte string engine libmbfl
HTTP input encoding translation disabled
libmbfl version 1.3.2
mbstring extension makes use of “streamable kanji code filter and converter”, which is distributed under the GNU Lesser General Public License version 2.1.
Directive Local Value Master Value
mbstring.detect_order no value no value
mbstring.encoding_translation Off Off
mbstring.func_overload 0 0
mbstring.http_input no value no value
mbstring.http_output no value no value
mbstring.http_output_conv_mimetypes ^(text/|application/xhtml+xml) ^(text/|application/xhtml+xml)
mbstring.internal_encoding no value no value
mbstring.language neutral neutral
mbstring.strict_detection Off Off
mbstring.substitute_character no value no value
And I am getting the same error whenever I call sitecake.php.