Is it possible that the DWG file was created with a different language than English? if so you could add such language to Windows control panel\Languages, Regional Settings
NLS is a font file format used by Microsoft Windows which contain information for National Language Support. NLS files are most commonly found in the Windows\system32 directory and they allows the transition and conversion between different character sets (see NLS Windows Terminology)
The NLS files required to convert the text entities and symbol table names in your drawing of code page 45 cannot be found or are not installed in your system. MicroStation can try to interpret text entities by using the default system code page however the result may not be correct.
When opening a DWG directly with MicroStation, the following error message may appear:
When importing or attaching a DWG file as a reference, the following may be indicated in the Message Center:
Modify the Windows 10 Regional Settings
Install the required language pack for the operating system from Language packs (Microsoft).
Note: Installing the required language pack in Windows installs the required NLS files. The language used when the drawing was created or last edited needs to be known. For instance, if the characters were created in Chinese, the Chinese language pack should be installed.
Other Language Sources